Revert "Revert "ARM: VIXL32: Use DontCare for SetFlags + fix for GenerateFrameEntry.""

Override Add in ArmVIXLMacroAssembler to improve 16-bit encodings.

This reverts commit 2f34995469e20a1ac342975856155f69995997ce.

Test: m test-art-host

Change-Id: Ief9f7576cd805104fd517a76b96d8a92f2208dfd
4 files changed