Initial internal member mangling

compiler/testData/codegen/boxWithJava/mangling/JavaClass.java

@@ -0,0 +1,5 @@
+public class JavaClass extends A {
+    public String test() {
+        return "Java";
+    }
+}

compiler/testData/codegen/boxWithJava/mangling/internalOverride.kt

@@ -0,0 +1,11 @@
+open class A {
+    internal open fun test(): String = "Kotlin"
+}
+
+fun box(): String {
+    if (A().test() != "Kotlin") return "fail 1: ${A().test()}"
+
+    if (JavaClass().test() != "Java") return "fail 2: ${JavaClass().test()}"
+
+    return "OK"
+}