Bug 1356843 - Fix -Wcomma warning in tools/profiler/lul/LulDwarf.cpp. r=jseward

clang's -Wcomma warning warns about suspicious use of the comma operator such as between two statements.

tools/profiler/lul/LulDwarf.cpp:604:15: warning: possible misuse of comma operator here [-Wcomma]

MozReview-Commit-ID: 6ZP79hgtrAD

--HG--
extra : rebase_source : 77028600c713aa3235c3729a5db7be0290df57e4
extra : source : e4536bbeb28050b38979a05b379f13eb4a12beee

tools/profiler/lul/LulDwarf.cpp

@@ -601,7 +601,7 @@ bool CallFrameInfo::RuleMap::HandleTransitionTo(
       if (*old_it->second != *new_it->second &&
           !new_it->second->Handle(handler, address, new_it->first))
         return false;
-      new_it++, old_it++;
+      new_it++; old_it++;
     }
   }
   // Finish off entries from this RuleMap with no counterparts in new_rules.