[turbofan] Load immortal heap objects from the heap roots.

[turbofan] Load immortal heap objects from the heap roots.

It's cheaper to materialize heap constants by loading from the roots
array instead of embedding the constant into the instruction stream, at
least on x64, arm and arm64.

Drive-by-fix: Also cleanup the materialize constant from frame
optimization.

R=dcarney@chromium.org

Committed: https://crrev.com/5d2de78a771b8ff1ac59fbdf634bffd01709b554
Cr-Commit-Position: refs/heads/master@{#27818}

[Benedikt Meurer, 2015-04-14 12:21:33]

Please take a look.

[dcarney, 2015-04-14 12:28:15]

lgtm

[Benedikt Meurer, 2015-04-14 12:32:17]

The CQ bit was checked by bmeurer@chromium.org

[commit-bot: I haz the power, 2015-04-14 12:32:29]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1088913002/1

[commit-bot: I haz the power, 2015-04-14 12:50:47]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-04-14 12:51:00]

Patchset 1 (id:??) landed as
https://crrev.com/5d2de78a771b8ff1ac59fbdf634bffd01709b554
Cr-Commit-Position: refs/heads/master@{#27818}