Fast ART x86 interpreter

Port of ART Dalvik-style interpreter for x86.
See Bill's patch for details
https://android-review.googlesource.com/#/c/188977/

Included fixes
https://android-review.googlesource.com/#/c/196153/
ART: Mterp read barrier fix + minor cleanup

https://android-review.googlesource.com/#/c/196501/


ART: Mterp - remove redundant null check

Change-Id: If447e3a14088559e3aa0b82cb2c91721bea586ee
Signed-off-by: Serguei Katkov <serguei.i.katkov@intel.com>