Implement support for X86II::MO_GOT_ABSOLUTE_ADDRESS. We get very

different formatting from the old asmprinter, but it should be 
semantically the same.  We used to get:

	popl	%eax
	addl	$_GLOBAL_OFFSET_TABLE_ + [.-.Lllvm$6.$piclabel], %eax
...

Now we get:

	popl	%eax
.Lpicbaseref6:
	addl	$(_GLOBAL_OFFSET_TABLE_ + (.Lpicbaseref6 - .Lllvm$6.$piclabel)), %eax
...

llvm-svn: 80905