Java: Fixed comparing potential matches when detecting duplicates of the extracted method (IDEA-182275)

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

@@ -0,0 +1,17 @@
+class WriteDifferentFieldsDuplicate {
+    Runnable x;
+    Runnable y;
+
+    private void foo() {
+        <selection>
+        if (x != null) {
+            x.run();
+            x = null;
+        }</selection>
+
+        if (y != null) {
+            y.run();
+            y = null;
+        }
+    }
+}