fix(perf): update end mark for rules (#1303)

With performanceTimer on, we get some nice usertiming measures added. But in #701, some _jerk_ picked an endpoint for rules that I, personally, think can be improved. :)

This moves the end mark of each rule to when the checks have synchronously finished. This change means we don't include the asynchronous bit afterwards, but that async bit is the subject of #1172.

For accurate timing, it makes more sense to keep these measures synchronous. It also makes reading the flame chart more logical.

Screenshots of before and after:
![image](https://user-images.githubusercontent.com/39191/50669976-6f0d9300-0f7d-11e9-8f60-24122a577084.png)



## Reviewer checks

**Required fields, to be filled out by PR reviewer(s)**
- [x] Follows the commit message policy, appropriate for next version
- [x] Has documentation updated, a DU ticket, or requires no documentation change
- [x] Includes new tests, or was unnecessary
- [x] Code is reviewed for security by: @WilcoFiers

lib/core/base/audit.js

@@ -368,13 +368,8 @@ function getRulesToRun(rules, context, options) {
  */
 function getDefferedRule(rule, context, options) {
 	// init performance timer of requested via options
-	let markStart;
-	let markEnd;
 	if (options.performanceTimer) {
-		markStart = 'mark_rule_start_' + rule.id;
-		markEnd = 'mark_rule_end_' + rule.id;
-		// mark start
-		axe.utils.performanceTimer.mark(markStart);
+		axe.utils.performanceTimer.mark('mark_rule_start_' + rule.id);
 	}
 
 	return (resolve, reject) => {
@@ -384,15 +379,6 @@ function getDefferedRule(rule, context, options) {
 			options,
 			// resolve callback for rule `run`
 			ruleResult => {
-				// if performance timer - mark end & measure
-				if (options.performanceTimer) {
-					axe.utils.performanceTimer.mark(markEnd);
-					axe.utils.performanceTimer.measure(
-						'rule_' + rule.id,
-						markStart,
-						markEnd
-					);
-				}
 				// resolve
 				resolve(ruleResult);
 			},

lib/core/base/rule.js

@@ -146,8 +146,10 @@ Rule.prototype.run = function(context, options, resolve, reject) {
 
 	const q = axe.utils.queue();
 	const ruleResult = new RuleResult(this);
-	const markStart = 'mark_runchecks_start_' + this.id;
-	const markEnd = 'mark_runchecks_end_' + this.id;
+	const markStart = 'mark_rule_start_' + this.id;
+	const markEnd = 'mark_rule_end_' + this.id;
+	const markChecksStart = 'mark_runchecks_start_' + this.id;
+	const markChecksEnd = 'mark_runchecks_end_' + this.id;
 
 	let nodes;
 
@@ -169,7 +171,7 @@ Rule.prototype.run = function(context, options, resolve, reject) {
 			'):',
 			axe.utils.performanceTimer.timeElapsed() + 'ms'
 		);
-		axe.utils.performanceTimer.mark(markStart);
+		axe.utils.performanceTimer.mark(markChecksStart);
 	}
 
 	nodes.forEach(node => {
@@ -212,12 +214,15 @@ Rule.prototype.run = function(context, options, resolve, reject) {
 	q.defer(resolve => setTimeout(resolve, 0));
 
 	if (options.performanceTimer) {
+		axe.utils.performanceTimer.mark(markChecksEnd);
 		axe.utils.performanceTimer.mark(markEnd);
 		axe.utils.performanceTimer.measure(
 			'runchecks_' + this.id,
-			markStart,
-			markEnd
+			markChecksStart,
+			markChecksEnd
 		);
+
+		axe.utils.performanceTimer.measure('rule_' + this.id, markStart, markEnd);
 	}
 
 	q.then(() => resolve(ruleResult)).catch(error => reject(error));