The JIT code generated by V8 is FPXX compliant
when v8 compiled with FPXX flag. This allows the code to
run in both FP=1 and FP=0 mode. It also alows v8 to be used
as a library by both FP32 and FP64 binaries.

BUG=

Review URL: https://codereview.chromium.org/1586223004

Cr-Commit-Position: refs/heads/master@{#33576}