Render platform name in multiplatform diagnostic tests

Prepend the platform name to the diagnostic in a common module, which is
reported when sources of that common module are analyzed as a part of the
platform source set: "<!JVM:...!> ... <!>". Fix some existing tests, mostly by
adding "impl" to implementations

compiler/testData/diagnostics/tests/multiplatform/headerClass/genericClassImplTypeAlias.kt

@@ -4,15 +4,15 @@
 // FILE: common.kt
 
 header class C1
-header class C2<A>
-header class C3<B>
-header class C4<D, E>
-header class C5<F, G>
-header class C6<H>
-header class C7<I>
-header class C8<J>
-header class C9<K>
-header class C10<L>
+header interface <!JVM:HEADER_WITHOUT_IMPLEMENTATION!>C2<!><A>
+header interface <!JVM:HEADER_WITHOUT_IMPLEMENTATION!>C3<!><B>
+header interface C4<D, E>
+header interface C5<F, G>
+header interface C6<H>
+header interface C7<I>
+header interface C8<J>
+header interface C9<K>
+header interface C10<L>
 
 // MODULE: m2-jvm(m1-common)
 // FILE: jvm.kt

compiler/testData/diagnostics/tests/multiplatform/headerClass/headerClassMember.kt

@@ -9,16 +9,16 @@ header class Foo {
 
 // MODULE: m2-jvm(m1-common)
 // FILE: jvm.kt
-class Foo {
-    val foo: String = "JVM"
+impl class Foo {
+    impl val foo: String = "JVM"
 
-    fun bar(x: Int): Int = x + 1
+    impl fun bar(x: Int): Int = x + 1
 }
 
 // MODULE: m3-js(m1-common)
 // FILE: js.kt
-class Foo {
-    val foo: String = "JS"
+impl class Foo {
+    impl val foo: String = "JS"
 
-    fun bar(x: Int): Int = x - 1
+    impl fun bar(x: Int): Int = x - 1
 }

compiler/testData/diagnostics/tests/multiplatform/headerClass/headerClassMember.txt

@@ -14,10 +14,10 @@ public final header class Foo {
 // -- Module: <m2-jvm> --
 package
 
-public final class Foo {
+public final impl class Foo {
     public constructor Foo()
     public final val foo: kotlin.String = "JVM"
-    public final fun bar(/*0*/ x: kotlin.Int): kotlin.Int
+    public final impl fun bar(/*0*/ x: kotlin.Int): kotlin.Int
     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
@@ -27,10 +27,10 @@ public final class Foo {
 // -- Module: <m3-js> --
 package
 
-public final class Foo {
+public final impl class Foo {
     public constructor Foo()
     public final val foo: kotlin.String = "JS"
-    public final fun bar(/*0*/ x: kotlin.Int): kotlin.Int
+    public final impl fun bar(/*0*/ x: kotlin.Int): kotlin.Int
     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

compiler/testData/diagnostics/tests/multiplatform/headerClass/simpleHeaderClass.kt

@@ -5,8 +5,8 @@ header class Foo
 
 // MODULE: m2-jvm(m1-common)
 // FILE: jvm.kt
-class Foo
+impl class Foo
 
 // MODULE: m3-js(m1-common)
 // FILE: js.kt
-class Foo
+impl class Foo

compiler/testData/diagnostics/tests/multiplatform/headerClass/simpleHeaderClass.txt

@@ -12,7 +12,7 @@ public final header class Foo {
 // -- Module: <m2-jvm> --
 package
 
-public final class Foo {
+public final impl class Foo {
     public constructor Foo()
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
@@ -23,7 +23,7 @@ public final class Foo {
 // -- Module: <m3-js> --
 package
 
-public final class Foo {
+public final impl class Foo {
     public constructor Foo()
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int

compiler/testData/diagnostics/tests/multiplatform/headerClass/superClass.kt

@@ -10,8 +10,8 @@ header class Foo : I, C, J
 
 // MODULE: m2-jvm(m1-common)
 // FILE: jvm.kt
-class Foo : I, C(), J
+impl class Foo : I, C(), J
 
 // MODULE: m3-js(m1-common)
 // FILE: js.kt
-class Foo : I, J, C()
+impl class Foo : I, J, C()

compiler/testData/diagnostics/tests/multiplatform/headerClass/superClass.txt

@@ -38,7 +38,7 @@ public open class C {
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }
 
-public final class Foo : I, C, J {
+public final impl class Foo : I, C, J {
     public constructor Foo()
     public open override /*3*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*3*/ /*fake_override*/ fun hashCode(): kotlin.Int
@@ -68,7 +68,7 @@ public open class C {
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }
 
-public final class Foo : I, J, C {
+public final impl class Foo : I, J, C {
     public constructor Foo()
     public open override /*3*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*3*/ /*fake_override*/ fun hashCode(): kotlin.Int

compiler/testData/diagnostics/tests/multiplatform/topLevelFun/headerAndImplInDIfferentPackages.kt

@@ -3,7 +3,7 @@
 // FILE: common.kt
 package common
 
-header fun foo()
+<!JS:HEADER_WITHOUT_IMPLEMENTATION, JVM:HEADER_WITHOUT_IMPLEMENTATION!>header fun foo()<!>
 
 // MODULE: m2-jvm(m1-common)
 // FILE: jvm.kt

compiler/testData/diagnostics/tests/multiplatform/topLevelFun/inlineFun.kt

@@ -2,7 +2,7 @@
 // MODULE: m1-common
 // FILE: common.kt
 
-inline header fun inlineFun()
+<!JVM:HEADER_WITHOUT_IMPLEMENTATION!>inline header fun inlineFun()<!>
 header fun nonInlineFun()
 
 // MODULE: m2-jvm(m1-common)