extract method: ensure folded replacement uses correct names, ensure invalid elements are skipped (IDEA-157519)

java/java-tests/testData/refactoring/extractMethod/FoldedWithNestedExpressions_after.java

@@ -0,0 +1,11 @@
+class Test {
+  void h(int i, String[] s, String[] t) {
+      final String s1 = newMethod(t[i], s[x.length()]);
+    System.out.println(s1);
+  }
+
+    private String newMethod(String x, String s) {
+        System.out.println(x);
+        return s;
+    }
+}