Output correct exception handling and frame info

on x86-64 linux.  This causes no regressions on
32 bit linux and 32 bit ppc.  More tests pass
on 64 bit ppc with no regressions.  I didn't
turn on eh on 64 bit linux because the intrinsics
needed to compile the eh runtime aren't done
yet.  But if you turn it on and link with the
mainline runtime then eh seems to work fine
on x86-64 linux with this patch.  Thanks to
Dale for testing.  The main point of the patch
is that if you output that some object is
encoded using 4 bytes you had better not output
8 bytes for it: the patch makes everything
consistent.

llvm-svn: 50825