[turbofan] Avoid generating dead BooleanNot nodes in typed lowering.

[turbofan] Avoid generating dead BooleanNot nodes in typed lowering.

Without this shortcut we generate one BooleanNot per JSUnaryNot with
number input, which is quite common in asm.js. These dead nodes then
survive until the late control reducer runs, and may prevent
optimizations in the mean time.

R=dcarney@chromium.org

Committed: https://crrev.com/936ae2b81499d04c66fa6df5938fde4e56db6fe3
Cr-Commit-Position: refs/heads/master@{#26911}

[Benedikt Meurer, 2015-02-27 10:02:58]

PTAL

[dcarney, 2015-02-27 10:03:51]

lgtm

[Benedikt Meurer, 2015-02-27 10:04:20]

The CQ bit was checked by bmeurer@chromium.org

[commit-bot: I haz the power, 2015-02-27 10:04:59]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/963713002/1

[commit-bot: I haz the power, 2015-02-27 10:25:01]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-02-27 10:25:13]

Patchset 1 (id:??) landed as
https://crrev.com/936ae2b81499d04c66fa6df5938fde4e56db6fe3
Cr-Commit-Position: refs/heads/master@{#26911}