Simplify stack check instruction in Crankshaft.

Simplify stack check instruction in Crankshaft.

So far we had two types of stack checks: one used for function entries
and one used at loop back edges which uses a deferred code object to
avoid spilling of registers in the loop.

After refactoring lazy deoptimization the first stack check can also
use deferred code. This change removes the first type of stack check
instruction in Crankshaft and uses a deferred stack check in all
places.
Committed: http://code.google.com/p/v8/source/detail?r=10118

[Jakob Kummerow, 2011-12-01 09:51:54]

LGTM