[region-isolation] Rename TransferNonSendable.cpp -> SendNonSendable.cpp.

Just beginning the elimination of the word transferred from the code base.

Author: gottesmm

lib/SILOptimizer/Mandatory/CMakeLists.txt

@@ -45,7 +45,7 @@ target_sources(swiftSILOptimizer PRIVATE
   RawSILInstLowering.cpp
   ReferenceBindingTransform.cpp
   ThunkLowering.cpp
-  TransferNonSendable.cpp
+  SendNonSendable.cpp
   LowerTupleAddrConstructor.cpp
   SILGenCleanup.cpp
   YieldOnceCheck.cpp