Fixed register allocation corner case.

The predicate CanBeSpilled had a bug, prohibiting the necessary spilling and
correct splitting of live ranges. Removed a redundant assertion immediately done
by the callee anyway.

Thanks to Slava for help with that issue and the entertaining historical
background of the whole story... ;-)

BUG=177883

Review URL: https://codereview.chromium.org/12631012

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@13891 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
MIPS: Fix debug mode related porting mistakes.

This commit fixes bugs in commit r13874 and in r13876.

BUG=

Review URL: https://codereview.chromium.org/12454010

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@13892 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
MIPS: Unify deoptimizer for stub failure trampoline frames.

Port r13887 (6d146270)

Original commit message:
This unifies the translation of a compiled stub frame to a stub failure
trampoline frame. Only the frame's register allocation is different on
each architecture and can be factored out.

BUG=

Review URL: https://codereview.chromium.org/12756002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@13893 ce2b1a6d-e550-0410-aec6-3dcde31c8c00