[optimizing compiler] Add CMP{L,G}_{FLOAT,DOUBLE}

Adds:
- float comparison for arm, x86, x86_64 backends.
- ucomis{s,d} assembly to x86 and x86_64.
- vmstat assebmly for thumb2
- new assembly tests

Change-Id: Ie3e19d0c08b3b875cd0a4be4ee4e9c8a4a076290
21 files changed