Merge pull request #6029 from Agoric/6028-gc-not-defined

fix(swingset): don't un-expose 'gc', to stop intermittent test failures

packages/SwingSet/src/lib-nodejs/engine-gc.js

@@ -7,8 +7,13 @@ if (typeof bestGC !== 'function') {
   // Node.js v8 wizardry.
   v8.setFlagsFromString('--expose_gc');
   bestGC = vm.runInNewContext('gc');
-  // Hide the gc global from new contexts/workers.
-  v8.setFlagsFromString('--no-expose_gc');
+  // We leave --expose_gc turned on, otherwise AVA's shared workers
+  // may race and disable it before we manage to extract the
+  // binding. This won't cause 'gc' to be visible to new Compartments
+  // because SES strips out everything it doesn't recognize.
+
+  // // Hide the gc global from new contexts/workers.
+  // v8.setFlagsFromString('--no-expose_gc');
 }
 
 // Export a const.