Fix ContainerTypeMask== and ContainerTypeMask.hashCode.

sdk/lib/_internal/compiler/implementation/util/util.dart

Index: sdk/lib/_internal/compiler/implementation/util/util.dart
===================================================================
--- sdk/lib/_internal/compiler/implementation/util/util.dart	(revision 30759)
+++ sdk/lib/_internal/compiler/implementation/util/util.dart	(working copy)
@@ -284,9 +284,10 @@
   buffer.write(string);
 }
 
-int computeHashCode(part1, [part2, part3, part4]) {
+int computeHashCode(part1, [part2, part3, part4, part5]) {
   return (part1.hashCode
           ^ part2.hashCode
           ^ part3.hashCode
-          ^ part4.hashCode) & 0x3fffffff;
+          ^ part4.hashCode
+          ^ part5.hashCode) & 0x3fffffff;
 }