Fix some warnings in the core library identified by the static analyzer.

runtime/lib/growable_array.dart

Index: runtime/lib/growable_array.dart
diff --git a/runtime/lib/growable_array.dart b/runtime/lib/growable_array.dart
index 0e186c17afe971dfa42b752ac8ee2f5096e4d8a5..b87e6b954f6fad4b15fc51820411eb2de43226e8 100644
--- a/runtime/lib/growable_array.dart
+++ b/runtime/lib/growable_array.dart
@@ -8,7 +8,7 @@ class GrowableObjectArray<T> implements List<T> {
         "GrowableObjectArray can only be allocated by the VM");
   }
 
-  void copyFrom(List<Object> src, int srcStart, int dstStart, int count) {
+  void copyFrom(List src, int srcStart, int dstStart, int count) {
     Arrays.copy(src, srcStart, this, dstStart, count);
   }