prevent illegal instruction exception when no measurements have been conducted

qdp_project/src/Benchmark.cpp

@@ -133,8 +133,10 @@ void process_timings(
             }
         }
 
-        *scana_run /= scana_rc;
-        *scana_wait /= scana_rc;
+        if (scana_rc != 0) {
+            *scana_run /= scana_rc;
+            *scana_wait /= scana_rc;
+        }
     }
     {
         uint64_t scanb_rc = 0;
@@ -147,8 +149,10 @@ void process_timings(
             }
         }
 
-        *scana_run /= scanb_rc;
-        *scana_wait /= scanb_rc;
+        if (scanb_rc != 0) {
+            *scana_run /= scanb_rc;
+            *scana_wait /= scanb_rc;
+        }
     }
     {
         uint64_t aggrj_rc = 0;
@@ -161,8 +165,10 @@ void process_timings(
             }
         }
 
-        *aggrj_run /= aggrj_rc;
-        *aggrj_wait /= aggrj_rc;
+        if (aggrj_rc != 0) {
+            *aggrj_run /= aggrj_rc;
+            *aggrj_wait /= aggrj_rc;
+        }
     }
 }