MIPS: Fix register usage in commit r14239.

BUG=

Review URL: https://codereview.chromium.org/14046006

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@14245 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Remove unnecessary BailoutIds.

BUG=

Review URL: https://codereview.chromium.org/14222007

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@14246 ce2b1a6d-e550-0410-aec6-3dcde31c8c00