x87 FPU converts the SNaN to QNaN automatically when loading SNaN from memmory. This function caused v8 x87 port can't distinguish the
  Hole NaN (V8 used SNaN for it) from Javascript visible NaNs (V8 used QNaN for it).

  Many test cases failed in this function for v8 x87 port. It's a big effort to refactor all code of x87 FPU loads value from memmory to
  fix this issue.

  So here's a temporary workaround for it, what's this CL does are:
  1. Removed all previous x87 workaround of this issue.
  2. Used SNaN of MIPS which is a not used QNaN in v8 x87 port as the Hole NaN for v8 x87 port.
  3. This CL is only local to x87 port.

BUG=

Review-Url: https://codereview.chromium.org/2033133004
Cr-Commit-Position: refs/heads/master@{#36697}