tests: rename _fixtures/vendor to _fixtures/internal

Some tests used a fake vendor directory placed inside _fixtures to
import some support packages.
In go.mod mode vendor directory are only supported on the root of the
project, which breaks some of our tests.
Since vendor directories outside the root of the project are so rare
anyway it's possible that a future version of go will stop supporting
it even in GOPATH mode.
Also it was weird and unnecessary in the first place anyawy.

_fixtures/consts.go

 package main
 
 import (
-	"dir0/pkg"
 	"fmt"
+	"github.com/derekparker/delve/_fixtures/internal/dir0/pkg"
 	"runtime"
 )
 

_fixtures/dotpackagesiface.go

 package main
 
 import (
-	"dir.io"
-	"dir.io/io.io"
 	"fmt"
+	"github.com/derekparker/delve/_fixtures/internal/dir.io"
+	"github.com/derekparker/delve/_fixtures/internal/dir.io/io.io"
 	"runtime"
 )
 

_fixtures/pkgrenames.go

@@ -8,9 +8,9 @@ import (
 	pkg1 "go/ast"
 	pkg2 "net/http"
 
-	"dir0/pkg"
-	"dir0/renamedpackage"
-	dir1pkg "dir1/pkg"
+	"github.com/derekparker/delve/_fixtures/internal/dir0/pkg"
+	"github.com/derekparker/delve/_fixtures/internal/dir0/renamedpackage"
+	dir1pkg "github.com/derekparker/delve/_fixtures/internal/dir1/pkg"
 )
 
 func main() {

service/test/variables_test.go

@@ -978,20 +978,20 @@ func TestPackageRenames(t *testing.T) {
 		{"amap", true, "interface {}(map[go/ast.BadExpr]net/http.Request) [{From: 2, To: 3}: *{Method: \"othermethod\", …", "", "interface {}", nil},
 
 		// Package name that doesn't match import path
-		{"iface3", true, `interface {}(*github.com/derekparker/delve/_fixtures/vendor/dir0/renamedpackage.SomeType) *{A: true}`, "", "interface {}", nil},
+		{"iface3", true, `interface {}(*github.com/derekparker/delve/_fixtures/internal/dir0/renamedpackage.SomeType) *{A: true}`, "", "interface {}", nil},
 
 		// Interfaces to anonymous types
 		{"amap2", true, "interface {}(*map[go/ast.BadExpr]net/http.Request) *[{From: 2, To: 3}: *{Method: \"othermethod\", …", "", "interface {}", nil},
-		{"dir0someType", true, "interface {}(*github.com/derekparker/delve/_fixtures/vendor/dir0/pkg.SomeType) *{X: 3}", "", "interface {}", nil},
-		{"dir1someType", true, "interface {}(github.com/derekparker/delve/_fixtures/vendor/dir1/pkg.SomeType) {X: 1, Y: 2}", "", "interface {}", nil},
-		{"amap3", true, "interface {}(map[github.com/derekparker/delve/_fixtures/vendor/dir0/pkg.SomeType]github.com/derekparker/delve/_fixtures/vendor/dir1/pkg.SomeType) [{X: 4}: {X: 5, Y: 6}, ]", "", "interface {}", nil},
-		{"anarray", true, `interface {}([2]github.com/derekparker/delve/_fixtures/vendor/dir0/pkg.SomeType) [{X: 1},{X: 2}]`, "", "interface {}", nil},
-		{"achan", true, `interface {}(chan github.com/derekparker/delve/_fixtures/vendor/dir0/pkg.SomeType) chan github.com/derekparker/delve/_fixtures/vendor/dir0/pkg.SomeType 0/0`, "", "interface {}", nil},
-		{"aslice", true, `interface {}([]github.com/derekparker/delve/_fixtures/vendor/dir0/pkg.SomeType) [{X: 3},{X: 4}]`, "", "interface {}", nil},
-		{"afunc", true, `interface {}(func(github.com/derekparker/delve/_fixtures/vendor/dir0/pkg.SomeType, github.com/derekparker/delve/_fixtures/vendor/dir1/pkg.SomeType)) main.main.func1`, "", "interface {}", nil},
-		{"astruct", true, `interface {}(*struct { A github.com/derekparker/delve/_fixtures/vendor/dir1/pkg.SomeType; B github.com/derekparker/delve/_fixtures/vendor/dir0/pkg.SomeType }) *{A: github.com/derekparker/delve/_fixtures/vendor/dir1/pkg.SomeType {X: 1, Y: 2}, B: github.com/derekparker/delve/_fixtures/vendor/dir0/pkg.SomeType {X: 3}}`, "", "interface {}", nil},
-		{"astruct2", true, `interface {}(*struct { github.com/derekparker/delve/_fixtures/vendor/dir1/pkg.SomeType; X int }) *{SomeType: github.com/derekparker/delve/_fixtures/vendor/dir1/pkg.SomeType {X: 1, Y: 2}, X: 10}`, "", "interface {}", nil},
-		{"iface2iface", true, `interface {}(*interface { AMethod(int) int; AnotherMethod(int) int }) **github.com/derekparker/delve/_fixtures/vendor/dir0/pkg.SomeType {X: 4}`, "", "interface {}", nil},
+		{"dir0someType", true, "interface {}(*github.com/derekparker/delve/_fixtures/internal/dir0/pkg.SomeType) *{X: 3}", "", "interface {}", nil},
+		{"dir1someType", true, "interface {}(github.com/derekparker/delve/_fixtures/internal/dir1/pkg.SomeType) {X: 1, Y: 2}", "", "interface {}", nil},
+		{"amap3", true, "interface {}(map[github.com/derekparker/delve/_fixtures/internal/dir0/pkg.SomeType]github.com/derekparker/delve/_fixtures/internal/dir1/pkg.SomeType) [{X: 4}: {X: 5, Y: 6}, ]", "", "interface {}", nil},
+		{"anarray", true, `interface {}([2]github.com/derekparker/delve/_fixtures/internal/dir0/pkg.SomeType) [{X: 1},{X: 2}]`, "", "interface {}", nil},
+		{"achan", true, `interface {}(chan github.com/derekparker/delve/_fixtures/internal/dir0/pkg.SomeType) chan github.com/derekparker/delve/_fixtures/internal/dir0/pkg.SomeType 0/0`, "", "interface {}", nil},
+		{"aslice", true, `interface {}([]github.com/derekparker/delve/_fixtures/internal/dir0/pkg.SomeType) [{X: 3},{X: 4}]`, "", "interface {}", nil},
+		{"afunc", true, `interface {}(func(github.com/derekparker/delve/_fixtures/internal/dir0/pkg.SomeType, github.com/derekparker/delve/_fixtures/internal/dir1/pkg.SomeType)) main.main.func1`, "", "interface {}", nil},
+		{"astruct", true, `interface {}(*struct { A github.com/derekparker/delve/_fixtures/internal/dir1/pkg.SomeType; B github.com/derekparker/delve/_fixtures/internal/dir0/pkg.SomeType }) *{A: github.com/derekparker/delve/_fixtures/internal/dir1/pkg.SomeType {X: 1, Y: 2}, B: github.com/derekparker/delve/_fixtures/internal/dir0/pkg.SomeType {X: 3}}`, "", "interface {}", nil},
+		{"astruct2", true, `interface {}(*struct { github.com/derekparker/delve/_fixtures/internal/dir1/pkg.SomeType; X int }) *{SomeType: github.com/derekparker/delve/_fixtures/internal/dir1/pkg.SomeType {X: 1, Y: 2}, X: 10}`, "", "interface {}", nil},
+		{"iface2iface", true, `interface {}(*interface { AMethod(int) int; AnotherMethod(int) int }) **github.com/derekparker/delve/_fixtures/internal/dir0/pkg.SomeType {X: 4}`, "", "interface {}", nil},
 
 		{`"dir0/pkg".A`, false, "0", "", "int", nil},
 		{`"dir1/pkg".A`, false, "1", "", "int", nil},
@@ -1010,7 +1010,7 @@ func TestPackageRenames(t *testing.T) {
 			if ver.Major > 0 && !ver.AfterOrEqual(goversion.GoVersion{1, 9, -1, 0, 0, ""}) {
 				// before 1.9 embedded struct field have fieldname == type
 				if tc.name == "astruct2" {
-					tc.value = `interface {}(*struct { github.com/derekparker/delve/_fixtures/vendor/dir1/pkg.SomeType; X int }) *{github.com/derekparker/delve/_fixtures/vendor/dir1/pkg.SomeType: github.com/derekparker/delve/_fixtures/vendor/dir1/pkg.SomeType {X: 1, Y: 2}, X: 10}`
+					tc.value = `interface {}(*struct { github.com/derekparker/delve/_fixtures/internal/dir1/pkg.SomeType; X int }) *{github.com/derekparker/delve/_fixtures/internal/dir1/pkg.SomeType: github.com/derekparker/delve/_fixtures/internal/dir1/pkg.SomeType {X: 1, Y: 2}, X: 10}`
 				}
 			}
 			variable, err := evalVariable(p, tc.name, pnormalLoadConfig)