[turbofan] greedy: heuristic for memory operands

[turbofan] greedy: heuristic for memory operands

When we have a memory operand (HasSpillOperand() == true), and it
doesn't need a register immediately, split in an optimal position, which
is outside the outermost possible loop - just like Linear does.

This results in some modest improvements in perf, when compared
to baseline greedy. In particular Jetstream zlib x64: 4.66%, Life
(Emscripten x64) 11%; largest regression is in AreWeFastYet x64: 8%
and Corrections (Emsccripten x32) 10%

BUG=

Committed: https://crrev.com/8937bfc1d165ff6d72dede1b0ce6f7c1ab9fb260
Cr-Commit-Position: refs/heads/master@{#30498}

[Mircea Trofin, 2015-09-01 08:02:45]

Patchset #1 (id:1) has been deleted

[Mircea Trofin, 2015-09-01 08:11:53]

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

[Benedikt Meurer, 2015-09-01 08:23:50]

lgtm

[Mircea Trofin, 2015-09-01 08:28:36]

The CQ bit was checked by mtrofin@chromium.org

[commit-bot: I haz the power, 2015-09-01 08:28:42]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1306823005/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1306823005/40001

[commit-bot: I haz the power, 2015-09-01 08:54:40]

Committed patchset #2 (id:40001)

[commit-bot: I haz the power, 2015-09-01 08:54:54]

Patchset 2 (id:??) landed as
https://crrev.com/8937bfc1d165ff6d72dede1b0ce6f7c1ab9fb260
Cr-Commit-Position: refs/heads/master@{#30498}

[Michael Achenbach, 2015-09-01 09:37:09]

A revert of this CL (patchset #2 id:40001) has been created in
https://codereview.chromium.org/1311813005/ by machenbach@chromium.org.

The reason for reverting is: [Sheriff] Breaks test with greedy allocator:
http://build.chromium.org/p/client.v8/builders/V8%20Linux%20-%20debug%20-%20g....