Do not reset stats in the middle of execution

Do not follow as per [2] at the below link
http://pages.cs.wisc.edu/~david/courses/cs752/Fall2015/wiki/index.php?n=Main.Homework3

If we follow the above, more finegrained set of stats are generated
which we are not interested in for this simulation run.

tests/test-progs/matrix-mult/mm.cpp

@@ -67,9 +67,7 @@ int main(int argc, char *argv[])
 
     cout << "Beginning multiply...";
 
-    m5_dumpreset_stats(0, 0);
     multiply(A, B, C, size);
-    m5_dumpreset_stats(0, 0);
 
     cout << "Done." << endl;