Optimize left shift of a constant: compute max value of right that does not overflow into Mint/Bigint.
Review URL: https://codereview.chromium.org//12212175

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@18525 260f80e4-7a28-3924-810f-c04153c831b5
3 files changed