Move continueWithExpression to IrBuilder.

+ cleanup of invocations
+ prepare analyzer2dart support for type operators

R=sigurdm@google.com

Review URL: https://codereview.chromium.org//693803003

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@41435 260f80e4-7a28-3924-810f-c04153c831b5
Make stdout/stderr async

This makes stdout.write and stderr.write async.

This effectively reverts https://code.google.com/p/dart/source/detail?r=33645

Reapplies r41350 after the dart2js batch-runner have been changed to handle
async stdout/stderr.

R=ricow@google.com
BUG=

Review URL: https://codereview.chromium.org//693793002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@41436 260f80e4-7a28-3924-810f-c04153c831b5
IR refactoring: consolidate all boxing and unboxing instructions.

BUG=
R=fschneider@google.com

Review URL: https://codereview.chromium.org//670263007

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@41437 260f80e4-7a28-3924-810f-c04153c831b5