[Stackmaps][X86] Remove EFLAGS and IP registers from the live-out mask.
Remove the EFLAGS from the stackmap live-out mask. The EFLAGS register is not
supposed to be part of that set, because the X86 calling conventions mark the
register as NOT preserved.
Also remove the IP registers, since spilling and restoring those doesn't really
make any sense.
Related to rdar://problem/21019635.