Support `external` modifier in descriptor renderer. Update test data.

compiler/testData/diagnostics/testsWithJsStdLib/native/nested.txt

@@ -12,9 +12,9 @@ public object O {
 public final class TopLevel {
     public constructor TopLevel()
     public final val x: kotlin.String = "a"
-    public final val y: kotlin.String
+    public external final val y: kotlin.String
     public final val O.u: kotlin.String
-    public final val O.v: kotlin.String
+    public external final val O.v: kotlin.String
     public final external fun bar(): kotlin.Int
     @kotlin.js.native public final fun baz(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
@@ -40,9 +40,9 @@ public final class TopLevel {
 public final class TopLevelNative {
     public constructor TopLevelNative()
     public final val x: kotlin.String = "a"
-    public final val y: kotlin.String
+    public external final val y: kotlin.String
     public final val O.u: kotlin.String
-    public final val O.v: kotlin.String
+    public external final val O.v: kotlin.String
     public final external fun bar(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public final fun foo(): kotlin.Int

compiler/testData/diagnostics/testsWithJsStdLib/native/optionlBody/native.txt

 package
 
-public val baz: kotlin.Int
-public val boo: kotlin.Int
-public val kotlin.Int.baz: kotlin.Int
+public external val baz: kotlin.Int
+public external val boo: kotlin.Int
+public external val kotlin.Int.baz: kotlin.Int
 public external fun bar(): kotlin.Unit
 public external fun foo(): kotlin.Unit
 public external fun kotlin.String.bar(): kotlin.Int

compiler/testData/diagnostics/testsWithStdLib/native/nonFunction.txt

 package
 
-public val foo: kotlin.Int = 23
+public external val foo: kotlin.Int = 23
 
-public final class A {
+public external final class A {
     public constructor A()
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
@@ -11,12 +11,12 @@ public final class A {
 
 public final class B {
     public constructor B()
-    public final val foo: kotlin.Int = 23
+    public external final val foo: kotlin.Int = 23
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 
-    public final class A {
+    public external final class A {
         public constructor A()
         public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
         public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int

core/descriptors/src/org/jetbrains/kotlin/renderer/DescriptorRendererImpl.kt

@@ -515,6 +515,12 @@ internal class DescriptorRendererImpl(
         }
     }
 
+    private fun renderExternal(memberDescriptor: MemberDescriptor, builder: StringBuilder) {
+        if (memberDescriptor.isExternal) {
+            builder.append("external ")
+        }
+    }
+
     private fun renderLateInit(propertyDescriptor: PropertyDescriptor, builder: StringBuilder) {
         if (propertyDescriptor.isLateInit) {
             builder.append("lateinit ")
@@ -528,9 +534,7 @@ internal class DescriptorRendererImpl(
         if (functionDescriptor.isInfix && (functionDescriptor.overriddenDescriptors.none { it.isInfix } || alwaysRenderModifiers)) {
             builder.append("infix ")
         }
-        if (functionDescriptor.isExternal) {
-            builder.append("external ")
-        }
+        renderExternal(functionDescriptor, builder)
         if (functionDescriptor.isInline) {
             builder.append("inline ")
         }
@@ -839,6 +843,7 @@ internal class DescriptorRendererImpl(
                 builder.append("const ")
             }
 
+            renderExternal(property, builder)
             renderModalityForCallable(property, builder)
             renderOverride(property, builder)
             renderLateInit(property, builder)
@@ -984,9 +989,7 @@ internal class DescriptorRendererImpl(
     }
 
     private fun renderAccessorModifiers(descriptor: PropertyAccessorDescriptor, builder: StringBuilder) {
-        if (descriptor.isExternal) {
-            builder.append("external ")
-        }
+        renderExternal(descriptor, builder)
     }
 
     /* STUPID DISPATCH-ONLY VISITOR */