Change deoptimize entrypoint to save everything.

Change deoptimize entrypoint to save everything.

And implement FPU register retrieval from stack on x86.

On Nexus 9, AOSP ToT, the boot.oat size reduction is
  prebuilt multi-part boot image:
    - 32-bit boot.oat: -20KiB (-0.03%)
    - 64-bit boot.oat: -45KiB (-0.06%)
  on-device built single boot image:
    - 32-bit boot.oat: -24KiB (-0.04%)
    - 64-bit boot.oat: -36KiB (-0.05%)

Test: Run ART test suite on host and Nexus 9.
Bug: 30212852
Change-Id: I5d98e2a24363136d73dfec6100ab02f8eb101911