CreateLocalVarFromInstanceofAction: use EquivalenceChecker which is more robust (in particular against parentheses)

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/createLocalVarFromInstanceof/before6p.java

@@ -0,0 +1,8 @@
+// "Insert '(Runnable)this' declaration" "false"
+class C {
+  void f() {
+      if ((this) instanceof Runnable<caret>) {
+        Object o = (Runnable)this;
+      }
+  }
+}