Also includes minor changes to regexp-macro-assembler.h.

Builds, but won't run until mips port submission is complete. Has
been tested externally.

BUG=
TEST=

Review URL: http://codereview.chromium.org//7038004

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@7907 ce2b1a6d-e550-0410-aec6-3dcde31c8c00