[SILOpt] Removed unreachable bailouts.

Now that supportsMoveOnlyTypes is always true, these bailouts can't be
reached.  Delete the bailouts and the predicate.

lib/SILOptimizer/Mandatory/MoveOnlyTempAllocationFromLetTester.cpp

@@ -34,10 +34,6 @@ struct MoveOnlyTempAllocationFromLetTester : SILFunctionTransform {
   void run() override {
     auto *fn = getFunction();
 
-    // Only run this pass if the move only language feature is enabled.
-    if (!fn->getASTContext().supportsMoveOnlyTypes())
-      return;
-
     // Don't rerun diagnostics on deserialized functions.
     if (getFunction()->wasDeserializedCanonical())
       return;