MIPS: Enable optimization of top-level code and generate deoptimization support lazily.

MIPS: Enable optimization of top-level code and generate deoptimization support lazily.

Port r10700 (c976fbd5).

Original commit message:
This change enables optimization of top-level and eval-code. For this to work, it adds
support for declaring global variables in optimized code.

At the same time it disables the eager generation of deoptimization support data
in the full code generator (originally introduced in
r10040). This speeds up initial compilation and saves
memory for functions that won't be optimized. It requires
recompiling the function with deoptimization
support when we decide to optimize it.

BUG=
TEST=
Review URL: https://chromiumcodereview.appspot.com/9418006

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@10773 ce2b1a6d-e550-0410-aec6-3dcde31c8c00