rename Memo/Count to AnonGlobalIDs/NextAnonGlobalID to be more

descriptive.  Thange them to keep track of the ID of a global that is
assigned, not the first mangled name returned for it.  Without doing this,
we are required to always use the same suffix for a global that gets 
mangled.  This means that we can mangle the same global once with $stub
and another time with $non_lazy_ptr or whatever.

llvm-svn: 75561