Unify sorted asserts to use the existing atomic pattern

These are all benign races and only visible in !NDEBUG. tsan complains
about it, but a simple atomic bool is sufficient to make it happy.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@335823 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed