[turbofan] Greedy: using hints

[turbofan] Greedy: using hints

This is a rudimentary introduction of hints. Primarily this helps with
allocating on the same register variables are defined (from instructions)
For dealing with phis, we need to introduce groups, in a subsequent
CL.

From the last CL (memory ops heuristics), this CL improves some
benchmarks - notably Life (11.94%) in Emscripten x64, and Memops
(Emscripten), 24% on x86; notable regressions: Memops in
AreWeFastYet (-14%, x64) and Corrections -25% on x86.

BUG=

Committed: https://crrev.com/038f5eaf3bd6796ed6b7519de83c21d4e1f54850
Cr-Commit-Position: refs/heads/master@{#30534}

[Mircea Trofin, 2015-09-01 13:29:45]

Patchset #1 (id:1) has been deleted

[Mircea Trofin, 2015-09-01 13:29:52]

Patchset #1 (id:20001) has been deleted

[Mircea Trofin, 2015-09-01 13:37:08]

mtrofin@chromium.org changed reviewers:
+ bmeurer@chromium.org, jarin@chromium.org

[Benedikt Meurer, 2015-09-02 06:43:09]

lgtm

[Mircea Trofin, 2015-09-02 06:43:24]

The CQ bit was checked by mtrofin@chromium.org

[commit-bot: I haz the power, 2015-09-02 06:43:33]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1329493004/60001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1329493004/60001

[commit-bot: I haz the power, 2015-09-02 07:12:53]

Committed patchset #2 (id:60001)

[commit-bot: I haz the power, 2015-09-02 07:13:04]

Patchset 2 (id:??) landed as
https://crrev.com/038f5eaf3bd6796ed6b7519de83c21d4e1f54850
Cr-Commit-Position: refs/heads/master@{#30534}

[Michael Hablich, 2015-09-02 08:34:48]

A revert of this CL (patchset #2 id:60001) has been created in
https://codereview.chromium.org/1324763005/ by hablich@chromium.org.

The reason for reverting is:
http://build.chromium.org/p/client.v8/builders/V8%20Linux%20-%20debug%20-%20g....