This is the first patch to put the needed bits in place to eventually allow code

to be aligned with optimal nops.  This patch does not change any functionality
and when the compiler is changed to use EmitCodeAlignment() it should also not
change the resulting output.  Once the compiler change is made and everything
looks good the next patch with the table of optimal X86 nops will be added to
WriteNopData() changing the output.  There are many FIXMEs in this patch which
will be removed when we have better target hooks (coming soon I hear).

llvm-svn: 96963