Pass condition result explicitly. Do not imply the existence of a status

Pass condition result explicitly. Do not imply the existence of a status
register. MIPS does not have one.
This is in preparation of another cl improving generated code for conditional
expressions and branches on MIPS.

R=srdjan@google.com

Committed: https://code.google.com/p/dart/source/detail?r=42346

[regis, 2014-12-11 21:29:05]

regis@google.com changed reviewers:
+ srdjan@google.com, zra@google.com

[regis, 2014-12-11 21:36:09]

regis@google.com changed reviewers:
+ srdjan@google.com, zra@google.com

[regis, 2014-12-11 21:36:57]

regis@google.com changed reviewers:
+ srdjan@google.com, zra@google.com

[regis, 2014-12-11 21:51:00]

regis@google.com changed reviewers:
+ srdjan@google.com, zra@google.com

[regis, 2014-12-11 22:12:32]

regis@google.com changed reviewers:
+ srdjan@google.com, zra@google.com

[regis, 2014-12-11 22:31:02]

regis@google.com changed reviewers:
+ srdjan@google.com, zra@google.com

[regis, 2014-12-12 00:10:13]

regis@google.com changed reviewers:
+ srdjan@google.com, zra@google.com

[regis, 2014-12-12 00:10:13]

This cl does not change generated code, but will allow for better code on MIPS
later.

This may not be the last refactoring/cleanup cl before the MIPS cl.

Thanks,
Regis

[srdjan, 2014-12-12 00:13:43]

srdjan@google.com changed reviewers:
+ fschneider@google.com

[srdjan, 2014-12-12 21:09:57]

lgtm

[regis, 2014-12-12 21:12:46]

Committed patchset #1 (id:1) manually as r42346 (presubmit successful).