chore: add memory debugging to mocha runner (#11722)

tools/mocha-runner/src/mocha-runner.ts

@@ -46,6 +46,7 @@ const {
   minTests,
   shard,
   reporter,
+  printMemory,
 } = yargs(hideBin(process.argv))
   .parserConfiguration({'unknown-options-as-args': true})
   .scriptName('@puppeteer/mocha-runner')
@@ -82,6 +83,10 @@ const {
     string: true,
     requiresArg: true,
   })
+  .option('print-memory', {
+    boolean: true,
+    default: false,
+  })
   .parseSync();
 
 function getApplicableTestSuites(
@@ -197,6 +202,10 @@ async function main() {
         'trace-warnings',
       ];
 
+      if (printMemory) {
+        args.push('-n', 'expose-gc');
+      }
+
       const specPattern = 'test/build/**/*.spec.js';
       const specs = globSync(specPattern, {
         ignore: !includeCdpTests ? 'test/build/cdp/**/*.spec.js' : undefined,