[Tests] Migrate backend-independent tests from native to compiler/testData.

^KT-65979

compiler/testData/codegen/box/innerClass/multipleModules.kt

@@ -0,0 +1,17 @@
+// MODULE: lib
+// FILE: lib.kt
+
+open class A {
+    open inner class Inner {
+        val x = "OK"
+    }
+}
+
+// MODULE: main(lib)
+// FILE: main.kt
+
+open class B : A() {
+    open inner class Inner : A.Inner()
+}
+
+fun box() = B().Inner().x