[arm64] Use ubfiz in ARM64 instruction selector

[arm64] Use ubfiz in ARM64 instruction selector

Select ubfiz for (x & mask) << imm where mask is contiguous and imm is non-zero.

BUG=

Committed: https://crrev.com/afd0367f5d219014433cb2dc1d84c50fa8196eac
Cr-Commit-Position: refs/heads/master@{#28755}

[martyn.capewell, 2015-06-02 10:00:14]

martyn.capewell@arm.com changed reviewers:
+ bmeurer@chromium.org, ulan@chromium.org

[Benedikt Meurer, 2015-06-02 10:14:11]

The CQ bit was checked by bmeurer@chromium.org

[Benedikt Meurer, 2015-06-02 10:14:12]

lgtm

[commit-bot: I haz the power, 2015-06-02 10:14:26]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1161643003/1

[commit-bot: I haz the power, 2015-06-02 10:57:43]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-06-02 10:57:56]

Patchset 1 (id:??) landed as
https://crrev.com/afd0367f5d219014433cb2dc1d84c50fa8196eac
Cr-Commit-Position: refs/heads/master@{#28755}