Don't add code dependencies eagerly for HCheckMaps.

Don't add code dependencies eagerly for HCheckMaps.

Instead of adding code dependencies on stable during
graph creation, we now add them during code generation
for those HCheckMaps that survived dead code elimination.

R=svenpanne@chromium.org

Committed: https://code.google.com/p/v8/source/detail?r=21139

[Benedikt Meurer, 2014-05-05 10:39:23]

PTAL

[Sven Panne, 2014-05-05 11:01:05]

lgtm

[Benedikt Meurer, 2014-05-05 11:03:29]

Committed patchset #3 manually as r21139 (presubmit successful).