MIPS64: [turbofan] Improve changes from and to Smi.

MIPS64: [turbofan] Improve changes from and to Smi.

The instruction selection for following sequences is
improved:

  113: Word64Sar(107, 91) : Internal/Any
  114: TruncateInt64ToInt32(113) : Signed32/UntaggedSigned32
  115: ChangeInt32ToFloat64(114) : Signed32/UntaggedFloat64

TEST=unittests/InstructionSelectorTest.ChangesFromToSmi
BUG=

Committed: https://crrev.com/4329a7c2cf2f5641284251afe388edd65b17a4d7
Cr-Commit-Position: refs/heads/master@{#30645}

[dusan.milosavljevic, 2015-09-08 16:47:44]

dusan.m.milosavljevic@gmail.com changed reviewers:
+ bmeurer@chromium.org, paul.lind@imgtec.com, titzer@chromium.org

[dusan.milosavljevic, 2015-09-08 16:47:45]

PTAL.

[paul.l..., 2015-09-08 18:22:43]

LGTM, thanks!

[dusan.milosavljevic, 2015-09-08 21:28:28]

The CQ bit was checked by dusan.m.milosavljevic@gmail.com

[commit-bot: I haz the power, 2015-09-08 21:28:37]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1318153006/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1318153006/1

[commit-bot: I haz the power, 2015-09-08 21:54:59]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-09-08 21:55:21]

Patchset 1 (id:??) landed as
https://crrev.com/4329a7c2cf2f5641284251afe388edd65b17a4d7
Cr-Commit-Position: refs/heads/master@{#30645}