MIPS: Move handler compilers to handler-compiler.

Port r23346 (fd75a28)

BUG=
R=verwaest@chromium.org

Review URL: https://codereview.chromium.org/501023002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@23364 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Introduce two new symbols for vector based ICs.

Vector based load ics need a premonomorphic and generic symbol.

R=verwaest@chromium.org

Review URL: https://codereview.chromium.org/505763002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@23365 ce2b1a6d-e550-0410-aec6-3dcde31c8c00