Fix test bot breakage from 36f351098cd50809658493d9b2e22a795874bab0

This addresses the issue found by: https://lab.llvm.org/buildbot/#/builders/192/builds/2309

GitOrigin-RevId: d4100f07da0526478a2b47242710f8a3f8d5e6a9
diff --git a/tools/dsymutil/DwarfLinkerForBinary.cpp b/tools/dsymutil/DwarfLinkerForBinary.cpp
index 5331eab..9841890 100644
--- a/tools/dsymutil/DwarfLinkerForBinary.cpp
+++ b/tools/dsymutil/DwarfLinkerForBinary.cpp
@@ -244,7 +244,7 @@
             }))
       return errorToErrorCode(std::move(NewE));
 
-    return Res;
+    return std::move(Res);
   }
 
   return ErrorOrObj.getError();