Make corelib_strong tests strong-mode compliant

tests/corelib_strong/iterable_take_while_test.dart

Index: tests/corelib_strong/iterable_take_while_test.dart
diff --git a/tests/corelib_strong/iterable_take_while_test.dart b/tests/corelib_strong/iterable_take_while_test.dart
index 3fb615ea63af8ca3bbc6a3cb7fa7c194b48b61b3..1407b5795f4bf17710dfa7da45503d4d614cea5d 100644
--- a/tests/corelib_strong/iterable_take_while_test.dart
+++ b/tests/corelib_strong/iterable_take_while_test.dart
@@ -118,15 +118,15 @@ main() {
   Expect.isFalse(it.moveNext());
   Expect.isNull(it.current);
 
-  takeWhileFalse = set2.takeWhile((x) => false);
-  it = takeWhileFalse.iterator;
-  Expect.isNull(it.current);
-  Expect.isFalse(it.moveNext());
-  Expect.isNull(it.current);
-
-  takeEverything = set2.takeWhile((x) => true);
-  it = takeEverything.iterator;
-  Expect.isNull(it.current);
-  Expect.isFalse(it.moveNext());
-  Expect.isNull(it.current);
+  var dynamicTakeWhileFalse = set2.takeWhile((x) => false);
+  var dynamicIt = dynamicTakeWhileFalse.iterator;
+  Expect.isNull(dynamicIt.current);
+  Expect.isFalse(dynamicIt.moveNext());
+  Expect.isNull(dynamicIt.current);
+
+  var dynamicTakeEverything = set2.takeWhile((x) => true);
+  dynamicIt = dynamicTakeEverything.iterator;
+  Expect.isNull(dynamicIt.current);
+  Expect.isFalse(dynamicIt.moveNext());
+  Expect.isNull(dynamicIt.current);
 }