[perf2bot] Pass `-f` flag to perf

Summary:
perf tool requires the input data to be owned by the current user or
root, otherwise it rejects the input. Use `-f` option to override this
behavior.

(cherry picked from FBD15160678)

bolt/src/DataAggregator.cpp

@@ -210,6 +210,7 @@ void DataAggregator::launchPerfProcess(StringRef Name, PerfProcessInfo &PPI,
     *Str++ = 0;
   } while (true);
 
+  Argv.push_back("-f");
   Argv.push_back("-i");
   Argv.push_back(PerfDataFilename.data());
   Argv.push_back(nullptr);