j2k: flatten test cases and testData directory structure

Move j2k/test/tests -> j2k/tests, j2k/test/testData -> j2k/testData

j2k/testData/fileOrElement/callChainExpression/libraryMethodCallFromInstance-settings.java

@@ -0,0 +1,18 @@
+// !forceNotNullTypes: false
+// !specifyLocalVariableTypeByDefault: true
+class Library {
+  void call() {}
+
+  String getString() { return ""; }
+}
+
+class User {
+  void main() {
+    Library lib = new Library();
+    lib.call();
+    lib.getString().isEmpty();
+
+    new Library().call();
+    new Library().getString().isEmpty();
+  }
+}