test: give more time to GC in test-shadow-realm-gc-module

When --node-builtin-modules-path is used, we read and create
new strings for builtins in each realm which increases the memory
usage. As a result GC may not be able to keep up with the
allocation done in the loop in the test.

As a workaround, give GC a bit more time by waiting for a timer
in the loop.

Author: joyeecheung

test/parallel/test-shadow-realm-gc-module.js

@@ -8,12 +8,16 @@
 
 const common = require('../common');
 const fixtures = require('../common/fixtures');
+const { promisify } = require('util');
 
+let wait = promisify(setTimeout);
 async function main() {
   const mod = fixtures.fileURL('es-module-shadow-realm', 'state-counter.mjs');
   for (let i = 0; i < 100; i++) {
     const realm = new ShadowRealm();
     await realm.importValue(mod, 'getCounter');
+    // Give the GC some breathing room.
+    await wait(10);
   }
 }