ART: Introduce stackmap with no DexRegInfo.

Some of safepoints don't need to have DexRegisterMap info;
this will decrease the stackmap size.

.oat file size reduction:
 - boot.oat:           -233 kb (-5.4%)
 - boot-framework.oat: -704 kb (-4.9%)

Test: 461-get-reference-vreg, 466-get-live-vreg.
Test: 543-env-long-ref, 616-cha*.
Test: test-art-target, +gc-stress.

Change-Id: Idbad355770e30a30dcf14127642e03ee666878b8
15 files changed