introduce: do not treat as same different foreach vars (IDEA-58421)

java/java-tests/testData/refactoring/introduceVariable/DifferentForeachParameters.java

@@ -0,0 +1,11 @@
+class A {
+  {
+    List<Integer> l = new ArrayList<Integer>();
+    for (Integer i : l) {
+      System.out.println(<selection>i.toString()</selection>);
+    }
+    for (Integer i : l) {
+      System.out.println(i.toString());
+    }
+  }
+}