benchmark: track exec time in next-tick-exec

The next-tick-exec benchmarks were meant to track nextTick execution
time but due to an error, they actually track addition and execution.

PR-URL: #20462
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

benchmark/process/next-tick-exec-args.js

@@ -5,8 +5,11 @@ const bench = common.createBenchmark(main, {
 });
 
 function main({ n }) {
+  function onNextTick(i) {
+    if (i + 1 === n)
+      bench.end(n);
+  }
 
-  bench.start();
   for (var i = 0; i < n; i++) {
     if (i % 4 === 0)
       process.nextTick(onNextTick, i, true, 10, 'test');
@@ -17,8 +20,6 @@ function main({ n }) {
     else
       process.nextTick(onNextTick, i);
   }
-  function onNextTick(i) {
-    if (i + 1 === n)
-      bench.end(n);
-  }
+
+  bench.start();
 }

benchmark/process/next-tick-exec.js

@@ -5,13 +5,14 @@ const bench = common.createBenchmark(main, {
 });
 
 function main({ n }) {
-
-  bench.start();
-  for (var i = 0; i < n; i++) {
-    process.nextTick(onNextTick, i);
-  }
   function onNextTick(i) {
     if (i + 1 === n)
       bench.end(n);
   }
+
+  for (var i = 0; i < n; i++) {
+    process.nextTick(onNextTick, i);
+  }
+
+  bench.start();
 }