[K/JS] Add warning for ES-modules on the klibgen stage on the uniqueness of the exported names from the module

compiler/ir/serialization.common/src/org/jetbrains/kotlin/backend/common/serialization/IrFileSerializer.kt

@@ -147,6 +147,10 @@ open class IrFileSerializer(
 
     protected val protoDebugInfoArray = arrayListOf<String>()
 
+    interface FileBackendSpecificMetadata {
+        fun toByteArray(): ByteArray
+    }
+
     sealed class XStatementOrExpression {
         abstract fun toByteArray(): ByteArray
 
@@ -1353,6 +1357,7 @@ open class IrFileSerializer(
     open fun backendSpecificExplicitRootExclusion(node: IrAnnotationContainer): Boolean = false
     open fun keepOrderOfProperties(property: IrProperty): Boolean = !property.isConst
     open fun backendSpecificSerializeAllMembers(irClass: IrClass) = false
+    open fun backendSpecificMetadata(irFile: IrFile): FileBackendSpecificMetadata? = null
 
     open fun memberNeedsSerialization(member: IrDeclaration): Boolean {
         val parent = member.parent
@@ -1454,15 +1459,16 @@ open class IrFileSerializer(
         serializeExpectActualSubstitutionTable(proto)
 
         return SerializedIrFile(
-            proto.build().toByteArray(),
-            file.packageFqName.asString(),
-            file.path,
-            IrMemoryArrayWriter(protoTypeArray.map { it.toByteArray() }).writeIntoMemory(),
-            IrMemoryArrayWriter(protoIdSignatureArray.map { it.toByteArray() }).writeIntoMemory(),
-            IrMemoryStringWriter(protoStringArray).writeIntoMemory(),
-            IrMemoryArrayWriter(protoBodyArray.map { it.toByteArray() }).writeIntoMemory(),
-            IrMemoryDeclarationWriter(topLevelDeclarations).writeIntoMemory(),
-            IrMemoryStringWriter(protoDebugInfoArray).writeIntoMemory()
+            fileData = proto.build().toByteArray(),
+            fqName = file.packageFqName.asString(),
+            path = file.path,
+            types = IrMemoryArrayWriter(protoTypeArray.map { it.toByteArray() }).writeIntoMemory(),
+            signatures = IrMemoryArrayWriter(protoIdSignatureArray.map { it.toByteArray() }).writeIntoMemory(),
+            strings = IrMemoryStringWriter(protoStringArray).writeIntoMemory(),
+            bodies = IrMemoryArrayWriter(protoBodyArray.map { it.toByteArray() }).writeIntoMemory(),
+            declarations = IrMemoryDeclarationWriter(topLevelDeclarations).writeIntoMemory(),
+            debugInfo = IrMemoryStringWriter(protoDebugInfoArray).writeIntoMemory(),
+            backendSpecificMetadata = backendSpecificMetadata(file)?.toByteArray(),
         )
     }