Update dart_backend_test after fixes to optional params.

TBR'ed.

R=antonm@google.com
BUG=

Review URL: https://codereview.chromium.org//16141005

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@23459 260f80e4-7a28-3924-810f-c04153c831b5

tests/compiler/dart2js/dart_backend_test.dart

@@ -612,7 +612,7 @@ class A {
   }
 }
 
-fooglobal(arg,[optionalarg = 7]) {
+fooglobal(arg,{optionalarg: 7}) {
   arg = 6;
 }
 
@@ -623,7 +623,7 @@ main() {
 }
 ''';
   var expectedResult =
-      'class B{var E;static C(A){A=5;}}D(A,[optionalarg=7]){A=6;}'
+      'class B{var E;static C(A){A=5;}}D(A,{optionalarg: 7}){A=6;}'
       'main(){new B().E;B.C(8);D(8);}';
   testDart2Dart(src, continuation:
       (String result) { Expect.equals(expectedResult, result); }, minify: true);