Update crc32_test.dart with Dart 2 constant name

Change-Id: I5a6a1bd7e027bab5e6833a5a3369aec469c3c0f0
Reviewed-on: https://dart-review.googlesource.com/65167
Reviewed-by: Bob Nystrom <rnystrom@google.com>
Commit-Queue: Leaf Petersen <leafp@google.com>
diff --git a/pkg/front_end/test/src/byte_store/crc32_test.dart b/pkg/front_end/test/src/byte_store/crc32_test.dart
index 0119bb8..0d209bb 100644
--- a/pkg/front_end/test/src/byte_store/crc32_test.dart
+++ b/pkg/front_end/test/src/byte_store/crc32_test.dart
@@ -33,6 +33,6 @@
   }
 
   test_string() {
-    expect(getCrc32(UTF8.encode('My very long test string.')), 0x88B8252E);
+    expect(getCrc32(utf8.encode('My very long test string.')), 0x88B8252E);
   }
 }