[Object] Remove a redundant return statement (NFC)

Identified with readability-redundant-control-flow.

llvm/lib/Object/Archive.cpp

@@ -1174,5 +1174,4 @@ BigArchive::BigArchive(MemoryBufferRef Source, Error &Err)
   }
   setFirstRegular(*I);
   Err = Error::success();
-  return;
 }