Merge pull request #9388 from bob-wilson/remove-zext-attribute

Remove the ZExt attribute for the MakeBoxUnique runtime function.

Author: bob-wilson

include/swift/Runtime/RuntimeFunctions.def

@@ -61,7 +61,7 @@ FUNCTION(MakeBoxUnique,
          DefaultCC,
          RETURNS(RefCountedPtrTy, OpaquePtrTy),
          ARGS(OpaquePtrTy, TypeMetadataPtrTy, SizeTy),
-         ATTRS(NoUnwind, ZExt))
+         ATTRS(NoUnwind))
 
 FUNCTION(DeallocBox, swift_deallocBox, DefaultCC,
          RETURNS(VoidTy),