Use our NuGet deployed reference assemblies

Removes our reliance on the machine installed reference assemblies.
Preferring the ones which we bring with us to the machine for both
Windows and Linux.

build/Targets/Dependencies.props

@@ -106,4 +106,4 @@
     <xunitrunnerconsoleVersion>2.2.0-beta4-build3444</xunitrunnerconsoleVersion>
     <xunitrunnervisualstudioVersion>2.2.0-beta4-build1194</xunitrunnervisualstudioVersion>
   </PropertyGroup>
-</Project>
\ No newline at end of file
+</Project>

build/Targets/Settings.props

@@ -35,6 +35,7 @@
          Use the Microsoft.Net.Compilers.props file with the fix checked into the repo instead of the one that comes along with the nuget package:
          $(NuGetPackageRoot)\Microsoft.Net.Compilers\$(ToolsetCompilerPackageVersion)\build\Microsoft.Net.Compilers.props -->
     <ToolsetCompilerPropsFilePath>$(MSBuildThisFileDirectory)Microsoft.Net.Compilers.props</ToolsetCompilerPropsFilePath>
+    <TargetFrameworkRootPath>$(NuGetPackageRoot)\RoslynTools.ReferenceAssemblies\$(RoslynToolsReferenceAssembliesVersion)\tools\Framework</TargetFrameworkRootPath>
 
     <VisualStudioVersion Condition="'$(VisualStudioVersion)' == ''">15.0</VisualStudioVersion>
     <VisualStudioReferenceMajorVersion Condition="'$(VisualStudioReferenceMajorVersion)' == ''">$(VisualStudioVersion.Substring(0, $(VisualStudioVersion.IndexOf('.'))))</VisualStudioReferenceMajorVersion>
@@ -93,9 +94,6 @@
 
   <!-- Unix specific settings -->
   <PropertyGroup Condition="'$(OS)' != 'Windows_NT'">
-    <!-- Point to the reference assemblies on unix -->
-    <TargetFrameworkRootPath>$(MSBuildBinPath)\reference-assemblies\Framework</TargetFrameworkRootPath>
-
     <DebugType>portable</DebugType>
   </PropertyGroup>
 

build/scripts/build-utils.ps1

@@ -45,21 +45,9 @@ function Ensure-MSBuild([switch]$xcopy = $false) {
     $both = Get-MSBuildKindAndDir -xcopy:$xcopy
     $msbuildDir = $both[1]
     switch ($both[0]) {
-        "xcopy" {
-            $p = Get-PackageDir "RoslynTools.ReferenceAssemblies"
-            ${env:TargetFrameworkRootPath} = Join-Path $p "tools\Framework"
-            break;
-        }
-        "vscmd" {
-            # Nothing to do here as the VS Dev CMD should set all appropriate environment
-            # variables.
-            break;
-        }
-        "vsinstall" {
-            # Nothing to do here as the VS Dev CMD should set all appropriate environment
-            # variables.
-            break;
-        }
+        "xcopy" { break; }
+        "vscmd" { break; }
+        "vsinstall" { break; }
         default {
             throw "Unknown MSBuild installation type $($both[0])"
         }