AST: switch to std::sort from llvm::array_pod_sort

Swap the `array_pod_sort` to `sort`.  `array_pod_sort` is meant to be
used with POD types only.  Switching to `std:sort` should be slightly
faster, and more importantly, allows the emission of the warnings on
Windows to be sorted identically to Linux and macOS.

Author: compnerd

lib/AST/GenericSignatureBuilder.cpp

@@ -6014,7 +6014,7 @@ Constraint<T> GenericSignatureBuilder::checkConstraintList(
   }
 
   // Sort the constraints, so we get a deterministic ordering of diagnostics.
-  llvm::array_pod_sort(constraints.begin(), constraints.end());
+  std::sort(constraints.begin(), constraints.end());
 
   // Find a representative constraint.
   auto representativeConstraint =