[TEST] Migrate duplicating javac tests to new test runners

Also minimize scope of DiagnosticUsingJavac tests to
 `compiler/testData/diagnostics/tests/javac`. This is fine since
 javac compilation mode is still not finished and no one not going to
 support it

compiler/testData/diagnostics/tests/javac/inheritance/InheritedInner.kt

@@ -0,0 +1,25 @@
+// FIR_IDENTICAL
+// FILE: a/x.java
+package a;
+
+public class x {
+
+    public class y {}
+
+}
+
+// FILE: a/b.java
+package a;
+
+public class b extends x {
+
+    public y getY() { return null; }
+
+}
+
+// FILE: test.kt
+package test
+
+import a.b
+
+fun test() = b().getY()