Merge pull request swiftlang#82312 from mikeash/swift-retain-method-tail-call

[Runtime] Tail call swift_retain in ObjC retain implementation.

Author: mikeash

include/swift/Runtime/HeapObject.h

@@ -1159,8 +1159,7 @@ swift_getMangledTypeName(const Metadata *type);
 #define STANDARD_OBJC_METHOD_IMPLS_FOR_SWIFT_OBJECTS \
 - (id)retain { \
   auto SELF = reinterpret_cast<HeapObject *>(self); \
-  swift_retain(SELF); \
-  return self; \
+  return reinterpret_cast<id>(swift_retain(SELF)); \
 } \
 - (oneway void)release { \
   auto SELF = reinterpret_cast<HeapObject *>(self); \