fix for: 1) "list[0] = 1" unparses to "list[] = 0 1"; 2) "a = list[0]" unparses to "a = list[][0]";
fix for:
1) "list[0] = 1" unparses to "list[] = 0 1";
2) "a = list[0]" unparses to "a = list[][0]";

BUG=
TEST=

Review URL: https://chromiumcodereview.appspot.com//10448008

git-svn-id: c93d8a2297af3b929165606efe145742a534bc71@8142 260f80e4-7a28-3924-810f-c04153c831b5

dart-archive/dart-sdk,dart-archive/dart-sdk,dart-lang/sdk,dart-archive/dart-sdk,dart-archive/dart-sdk,dart-archive/dart-sdk,dart-lang/sdk,dart-lang/sdk,dartino/dart-sdk,dart-lang/sdk,dartino/dart-sdk,dart-archive/dart-sdk,dartino/dart-sdk,dartino/dart-sdk,dartino/dart-sdk,dart-archive/dart-sdk,dart-lang/sdk,dart-lang/sdk,dart-archive/dart-sdk,dartino/dart-sdk,dartino/dart-sdk,dart-lang/sdk,dartino/dart-sdk,dart-archive/dart-sdk,dartino/dart-sdk,dart-lang/sdk