Fixes to wait-loop code

1) Add get_ptr_type() method to all wait flag types.
2) Flag in sleep_loc may change type by the time the resume is called from
   __kmp_null_resume_wrapper. We use get_ptr_type to obtain the real type
   and compare it to the casted object received. If they don't match, we know
   the flag has changed (already resumed and replaced by another flag). If they
   match, it doesn't hurt to go ahead and resume it.

Differential Revision: http://reviews.llvm.org/D14458

llvm-svn: 252487