[turbofan]: Fix bug in register hinting

[turbofan]: Fix bug in register hinting

Previously, UsePositions for Phis that are constant LiveRanges which are also used
as hints for other USePositions would always force-allocate the first register in
the allocatable register file to that range.

Committed: https://crrev.com/bfbc5e7c156aced651306645a349714f5a11e4cf
Cr-Commit-Position: refs/heads/master@{#30193}

[danno, 2015-08-17 12:12:28]

danno@chromium.org changed reviewers:
+ jarin@chromium.org

[danno, 2015-08-17 12:12:36]

PTAL

[Jarin, 2015-08-17 12:16:39]

lgtm. Thanks!

[danno, 2015-08-17 12:41:45]

The CQ bit was checked by danno@chromium.org

[commit-bot: I haz the power, 2015-08-17 12:41:55]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1289313003/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1289313003/20001

[commit-bot: I haz the power, 2015-08-17 12:44:05]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-08-17 12:44:11]

Patchset 2 (id:??) landed as
https://crrev.com/bfbc5e7c156aced651306645a349714f5a11e4cf
Cr-Commit-Position: refs/heads/master@{#30193}