Change the X86 asmprinter to use the mangler to apply suffixes like "$non_lazy_ptr"

Change the X86 asmprinter to use the mangler to apply suffixes like "$non_lazy_ptr"
to symbols instead of doing it with "printSuffixedName".  This gets us to the point
where there is a real separation between computing a symbol name and printing it,
something I need for MC printer stuff.

This patch also fixes a corner case bug where unnamed private globals wouldn't get
the private label prefix.

Next up, rename all uses of getValueName -> getMangledName for better greppability,
and then tackle the ppc/arm backends to eliminate "printSuffixedName".

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@75610 91177308-0d34-0410-b5e6-96231b3b80d8