Remove clang optimize off and loosen an error in the swift-version test.

(cherry picked from commit 58fd432)

Conflicts:
	test/sil-opt/swift-version.sil

Author: gottesmm

lib/SILOptimizer/Mandatory/TransferNonSendable.cpp

@@ -41,8 +41,6 @@
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/Support/Debug.h"
 
-#pragma clang optimize off
-
 using namespace swift;
 using namespace swift::PartitionPrimitives;
 using namespace swift::PatternMatch;