Prevent multiple waits callback delayed by one tick

To ensure the first wait doesn't checkpoint before the second is called

Author: matt-aitken

packages/core/src/v3/runtime/preventMultipleWaits.ts

@@ -21,6 +21,9 @@ export function preventMultipleWaits() {
     isExecutingWait = true;
 
     try {
+      //delay calling the callback by one tick
+      //(to ensure the first wait doesn't checkpoint before the second is called)
+      await Promise.resolve();
       return await cb();
     } finally {
       isExecutingWait = false;