Make corelib_strong tests strong-mode compliant

tests/corelib_strong/iterable_skip_while_test.dart

Index: tests/corelib_strong/iterable_skip_while_test.dart
diff --git a/tests/corelib_strong/iterable_skip_while_test.dart b/tests/corelib_strong/iterable_skip_while_test.dart
index d812300b02d128e21d852c9fb0ec2330b15c6a18..1dcd869776740db0d98f74978dfc1b7346adb367 100644
--- a/tests/corelib_strong/iterable_skip_while_test.dart
+++ b/tests/corelib_strong/iterable_skip_while_test.dart
@@ -134,15 +134,15 @@ main() {
   Expect.isFalse(it.moveNext());
   Expect.isNull(it.current);
 
-  skipWhileTrue = set2.skipWhile((x) => true);
-  it = skipWhileTrue.iterator;
-  Expect.isNull(it.current);
-  Expect.isFalse(it.moveNext());
-  Expect.isNull(it.current);
-
-  skipWhileFalse = set2.skipWhile((x) => false);
-  it = skipWhileFalse.iterator;
-  Expect.isNull(it.current);
-  Expect.isFalse(it.moveNext());
-  Expect.isNull(it.current);
+  var dynamicSkipWhileTrue = set2.skipWhile((x) => true);
+  var dynamicIt = dynamicSkipWhileTrue.iterator;
+  Expect.isNull(dynamicIt.current);
+  Expect.isFalse(dynamicIt.moveNext());
+  Expect.isNull(dynamicIt.current);
+
+  var dynamicSkipWhileFalse = set2.skipWhile((x) => false);
+  dynamicIt = dynamicSkipWhileFalse.iterator;
+  Expect.isNull(dynamicIt.current);
+  Expect.isFalse(dynamicIt.moveNext());
+  Expect.isNull(dynamicIt.current);
 }