MIPS64: Fix stack overflow on simulator when large number of locals are allocated.

TEST=mjsunit/limit-locals.js
BUG=
MIPS64: Silence all warnings in simulator.

(cherry picked from commit b6c1dcd302984dfc4572cdb715afa000e9928a8a)
MIPS64: Remove use of FLAG_sim_dbg_addr.

This removes the command line flag, which sped up test runs back the days
we had lots of unaligned errors.

More cleanup is still needed here.

Also, an un-related whitespace error is fixed.
MIPS64: Rename build target to mips64el.

This new name matches gnu usage, and what will be done in Android.
This name should be used in Chromium build system also.

(old name mipsel64).