Update tests to use std::isnan instead of isnan

Should fix compilation breakage after r14352

Review URL: https://codereview.chromium.org/14328044

Patch from Jochen Eisinger <jochen@chromium.org>.

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@14354 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Update arm and mips simulator to also use cmath

Review URL: https://codereview.chromium.org/14241029

Patch from Jochen Eisinger <jochen@chromium.org>.

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@14355 ce2b1a6d-e550-0410-aec6-3dcde31c8c00