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