[K/N][Tests] Move filecheck and cinterop tests to /native/

^KT-61259

native/native.tests/testData/codegen/cinterop/basics/mangling.kt

@@ -0,0 +1,24 @@
+// TARGET_BACKEND: NATIVE
+// MODULE: cinterop
+// FILE: mangling.def
+---
+
+// test mangling of special names
+
+enum _Companion {Companion, Any};
+enum _Companion companion = Companion;
+
+// MODULE: main(cinterop)
+// FILE: main.kt
+@file:OptIn(kotlinx.cinterop.ExperimentalForeignApi::class)
+import kotlinx.cinterop.*
+import kotlin.test.*
+import mangling.*
+
+fun box(): String {
+    companion = _Companion.`Companion$`
+    assertEquals(_Companion.`Companion$`, companion)
+
+    return "OK"
+}
+