issue 4817 fixed. Implemented raw strings with 'r' instead of '@' for dart2js

tests/compiler/dart2js/gvn_test.dart

Index: tests/compiler/dart2js/gvn_test.dart
diff --git a/tests/compiler/dart2js/gvn_test.dart b/tests/compiler/dart2js/gvn_test.dart
index ade16a0c7963bbba577d5fd01d1637292c5d59c8..c63b2c6708e929475d4ffd82220b4b2b29e691d7 100644
--- a/tests/compiler/dart2js/gvn_test.dart
+++ b/tests/compiler/dart2js/gvn_test.dart
@@ -4,7 +4,7 @@
 
 #import("compiler_helper.dart");
 
-const String TEST_ONE = @"""
+const String TEST_ONE = r"""
 void foo(bar) {
   for (int i = 0; i < 1; i++) {
     print(1 + bar);
@@ -15,7 +15,7 @@ void foo(bar) {
 
 main() {
   String generated = compile(TEST_ONE, 'foo');
-  RegExp regexp = const RegExp(@"1 \+ bar");
+  RegExp regexp = const RegExp(r"1 \+ bar");
   Iterator matches = regexp.allMatches(generated).iterator();
   Expect.isTrue(matches.hasNext());
   matches.next();