* fixes fatal message string; cleans comments because FIXMEs are bit irrelevant,
there is no reason to not trust MacroAssembler's
target_addr_for_insn, pd_patch_instruction

* removes movw/movt check for same target load register in NativeMovConstReg.
Andrey Petushkov's ARMv6 patch will add mov+3orr variant for Move, so the check
is starting to look very excessive