[Timers] TimerGroup::printJSONValues(): print mem timer with .mem suffix

[lebedev.ri]

Summary

We have just used .sys suffix for the previous timer, this is clearly a typo

[alexfh]

LG

llvm/trunk/lib/Support/Timer.cpp

for (const PrintRecord &R : TimersToPrint) {
     const TimeRecord &T = R.Time;
     printJSONValue(OS, R, ".wall", T.getWallTime());
     OS << delim;
     printJSONValue(OS, R, ".user", T.getUserTime());
     OS << delim;
     printJSONValue(OS, R, ".sys", T.getSystemTime());
     if (T.getMemUsed()) {
       OS << delim;
-      printJSONValue(OS, R, ".sys", T.getMemUsed());
+      printJSONValue(OS, R, ".mem", T.getMemUsed());
     }
   }
   TimersToPrint.clear();
   return delim;
 }
 
 const char *TimerGroup::printAllJSONValues(raw_ostream &OS, const char *delim) {
   sys::SmartScopedLock<true> L(*TimerLock);
   for (TimerGroup *TG = TimerGroupList; TG; TG = TG->Next)
     delim = TG->printJSONValues(OS, delim);
   return delim;
 }
 
 void TimerGroup::ConstructTimerLists() {
   (void)*NamedGroupedTimers;
 }