MIPS: Improve allocate locals to reduce code size.

TEST=
BUG=
R=plind44@gmail.com

Review URL: https://codereview.chromium.org/104713013

Patch from Dusan Milosavljevic <Dusan.Milosavljevic@rt-rk.com>.

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@18398 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
MIPS: Improve registers saving for safepoints in deferred code.

This reduces code size of initial snapshot by more than 25Kb.

Registers are saved or restored via common stubs, instead of doing it
through inlined push/pop instructions (one instruction per register) in
generated deferred code.

TEST=
BUG=
R=jkummerow@chromium.org, plind44@gmail.com

Review URL: https://codereview.chromium.org/109653013

Patch from Dusan Milosavljevic <Dusan.Milosavljevic@rt-rk.com>.

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@18399 ce2b1a6d-e550-0410-aec6-3dcde31c8c00