Check class source in bytecode listing tests

compiler/testData/codegen/bytecodeListing/inlineClasses/companionObjectInsideInlineClass.txt

@@ -1,5 +1,6 @@
 @kotlin.Metadata
 public final class Foo$Companion {
+    // source: 'companionObjectInsideInlineClass.kt'
     private method <init>(): void
     public synthetic method <init>(p0: kotlin.jvm.internal.DefaultConstructorMarker): void
     public final method funInCompanion(): void
@@ -8,6 +9,7 @@ public final class Foo$Companion {
 
 @kotlin.Metadata
 public final class Foo {
+    // source: 'companionObjectInsideInlineClass.kt'
     public final static @org.jetbrains.annotations.NotNull field Companion: Foo$Companion
     private final static field constValInCompanion: int
     private final field x: int