[Benchmarks] Speed up charts load

Dates can be compared directly as strings, it works. There is no need for expensive Date object creation and comparing Date objects.
Create latest runs lookup only once to reduce time complexity.

Author: PatKamin

devops/scripts/benchmarks/html/scripts.js

@@ -10,6 +10,7 @@ let suiteNames = new Set();
 let timeseriesData, barChartsData, allRunNames;
 let activeTags = new Set();
 let layerComparisonsData;
+let latestRunsLookup = new Map();
 
 // DOM Elements
 let runSelect, selectedRunsDiv, suiteFiltersContainer, tagFiltersContainer;
@@ -342,8 +343,7 @@ function createChartContainer(data, canvasId, type) {
     // Create and append extra info
     const extraInfo = document.createElement('div');
     extraInfo.className = 'extra-info';
-    latestRunsLookup = createLatestRunsLookup(benchmarkRuns);
-    extraInfo.innerHTML = generateExtraInfo(latestRunsLookup, data, 'benchmark');
+    extraInfo.innerHTML = generateExtraInfo(data, 'benchmark');
     details.appendChild(extraInfo);
 
     container.appendChild(details);
@@ -371,11 +371,10 @@ function createLatestRunsLookup(benchmarkRuns) {
     const latestRunsMap = new Map();
 
     benchmarkRuns.forEach(run => {
-        // Yes, we need to convert the date every time. I checked.
-        const runDate = new Date(run.date);
+        const runDate = run.date;
         run.results.forEach(result => {
             const label = result.label;
-            if (!latestRunsMap.has(label) || runDate > new Date(latestRunsMap.get(label).date)) {
+            if (!latestRunsMap.has(label) || runDate > latestRunsMap.get(label).date) {
                 latestRunsMap.set(label, {
                     run,
                     result
@@ -417,7 +416,7 @@ function getDisplayLabel(label, data, metadata) {
     return label;
 }
 
-function generateExtraInfo(latestRunsLookup, data, type = 'benchmark') {
+function generateExtraInfo(data, type = 'benchmark') {
     const labels = extractLabels(data);
 
     return labels.map(label => {
@@ -958,6 +957,7 @@ function initializeCharts() {
     barChartsData = processBarChartsData(benchmarkRuns);
     layerComparisonsData = processLayerComparisonsData(benchmarkRuns);
     allRunNames = [...new Set(benchmarkRuns.map(run => run.name))];
+    latestRunsLookup = createLatestRunsLookup(benchmarkRuns);
 
     // Set up active runs
     const runsParam = getQueryParam('runs');