MIPS: [turbofan] Add AllocateHeapNumberStub to avoid runtime call.

Port 983ca3f1e7bd8cbba45684d5c1642cd495ca9bc1
Port r25107

TEST=unittests
BUG=
R=paul.lind@imgtec.com

Review URL: https://codereview.chromium.org/699903002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@25118 ce2b1a6d-e550-0410-aec6-3dcde31c8c00