Remove a special case for OSAtomic functions. We can already bind and retrieve

Remove a special case for OSAtomic functions. We can already bind and retrieve
with the same binding key. The only trick here is that sometimes the Symbolic
region is stored in with an LocAsInteger wrapper. We unwrap that in
SVal::getAsLocSymbol().

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@111734 91177308-0d34-0410-b5e6-96231b3b80d8