Merged r13900, r13906 into 3.17 branch.

MIPS: fix NaN handling of Isolate::StackOverflow()

MIPS: Fix white space matching in latin-1 strings wrt \u00a0.

R=jkummerow@chromium.org
BUG=

Review URL: https://codereview.chromium.org/14161005

git-svn-id: https://v8.googlecode.com/svn/branches/3.17@14317 ce2b1a6d-e550-0410-aec6-3dcde31c8c00