Use first position in LAllocator ordering heuristic.

Use first position in LAllocator ordering heuristic.

This changes the tiebreaker for LAllocator's ordering heuristic of
live ranges to use the first use position instead of the first hinted
use position. Searching for the first hinted position introduces
unnecessary overhead.

R=jkummerow@chromium.org

Committed: http://code.google.com/p/v8/source/detail?r=14534

[Michael Starzinger, 2013-05-02 18:34:06]

OK, now I am just feeling stupid. There go several hours profiling the register
allocator for a single-line change. Or as someone on the team uses to phrase it:
"But you learned a lot". :)

[Jakob Kummerow, 2013-05-02 20:52:40]

lgtm

[Michael Starzinger, 2013-05-03 08:09:52]

Committed patchset #1 manually as r14534 (presubmit successful).