Remove saving/restoring of the context at function entry.

This is not needed anymore after I changed the current context
to always reside in a local variable.

Further simplifications and cleanup in the debugger.

This also fixes a bad memory retention problem with
non-capturing closures.

BUG=dartbug.com/18886
TEST=tests/language/vm/closure_memory_retention_test.dart
R=hausner@google.com

Review URL: https://codereview.chromium.org//695483003

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@41433 260f80e4-7a28-3924-810f-c04153c831b5
dart2js: Revert r36565 (Work-around for memory leak).

After fixing VM bug dartbug.com/18886 this work-around is not
needed anymore.

I tested dart2js tests in batch mode using the following command.

tools/test.py -mrelease -aia32 -cdart2js -rd8 --dart2js-batch

and it works fine.

Review URL: https://codereview.chromium.org//678083003

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@41434 260f80e4-7a28-3924-810f-c04153c831b5
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