Avoid read barrier for image HLoadClass
Concurrent copying baker:
X86_64 core-optimizing-pic.oat:
28583112 ->
27906824 (2.4% smaller)
Around 0.4% of 2.4% is from re-enabling kBootImageLinkTimeAddress,
kBootImageLinkTimePcRelative, and kBootImageAddress.
N6P boot.oat 32:
73042140 ->
71891956 (1.57% smaller)
N6P boot.oat 64:
83831608 ->
82531456 (1.55% smaller)
EAAC: 1252 -> 1245 (32 samples)
Bug:
29516974
Test: test-art-host CC baker, N6P booting
Change-Id: I9a196cf0157058836981c43c93872e9f0c4919aa