- Streamline comparisons in symbol table. - Avoid String::Equals method which considers the canonical bit.
- Streamline comparisons in symbol table.
- Avoid String::Equals method which considers the canonical bit.

BUG=
R=asiva@google.com

Review URL: https://codereview.chromium.org/1885433002 .

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