Revert "Be more careful about canonicalizing objects that come from core but may have been created between taking the full snapshot and taking the script snapshot."
Revert "Be more careful about canonicalizing objects that come from core but may have been created between taking the full snapshot and taking the script snapshot."

TBR=asiva@google.com

Review URL: https://codereview.chromium.org//606113004

git-svn-id: c93d8a2297af3b929165606efe145742a534bc71@40739 260f80e4-7a28-3924-810f-c04153c831b5

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