[turbofan] Remove context canonicalization hack from generic lowering.

[turbofan] Remove context canonicalization hack from generic lowering.

This hack doesn't help currently, since it only applies to asm.js where
we do function context specialization and there we already have a
canonicalized context (and the CodeGenerator materializes that from the
frame).

R=mstarzinger@chromium.org

Committed: https://crrev.com/d06591a2a3bc9643aa5785e1f8c01bd820b7c36a
Cr-Commit-Position: refs/heads/master@{#29025}

[Benedikt Meurer, 2015-06-15 11:59:47]

Hey Michi,

Removing another (now) useless hack. Please take a look.

Thanks,
Benedikt

[Michael Starzinger, 2015-06-15 12:03:17]

LGTM. Thanks!

[Benedikt Meurer, 2015-06-15 12:03:27]

The CQ bit was checked by bmeurer@chromium.org

[commit-bot: I haz the power, 2015-06-15 12:03:39]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1177033006/1

[commit-bot: I haz the power, 2015-06-15 12:21:31]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-06-15 12:21:55]

Patchset 1 (id:??) landed as
https://crrev.com/d06591a2a3bc9643aa5785e1f8c01bd820b7c36a
Cr-Commit-Position: refs/heads/master@{#29025}