[FIR JS] Prepare the test data for FIR

compiler/testData/diagnostics/testsWithJsStdLib/native/unusedParam/native.kt

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 external fun foo(a: String): Int = definedExternally
 
 external class Bar(b: Int, c: Char) {
@@ -9,4 +10,4 @@ external object Obj {
     object Nested {
         fun test2(g: Int) { definedExternally }
     }
-}
+}

compiler/testData/diagnostics/testsWithJsStdLib/native/unusedParam/nativeGetter.kt

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // !DIAGNOSTICS: -DEPRECATION
 @nativeGetter
 fun Int.foo(a: String): Int? = definedExternally

compiler/testData/diagnostics/testsWithJsStdLib/native/unusedParam/nativeInvoke.kt

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // !DIAGNOSTICS: -DEPRECATION
 @nativeInvoke
 fun Int.foo(a: String): Int = definedExternally

compiler/testData/diagnostics/testsWithJsStdLib/native/unusedParam/nativeSetter.kt

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // !DIAGNOSTICS: -DEPRECATION
 @nativeSetter
 fun Int.foo(a: String, v: Int): Int = definedExternally