fix: Remove redundant flush of microtask queue

Author: Sebastian Silbermann

src/pure.js

@@ -13,20 +13,6 @@ import act, {
 import {fireEvent} from './fire-event'
 import {getConfig, configure} from './config'
 
-function jestFakeTimersAreEnabled() {
-  /* istanbul ignore else */
-  if (typeof jest !== 'undefined' && jest !== null) {
-    return (
-      // legacy timers
-      setTimeout._isMockFunction === true || // modern timers
-      // eslint-disable-next-line prefer-object-has-own -- No Object.hasOwn in all target environments we support.
-      Object.prototype.hasOwnProperty.call(setTimeout, 'clock')
-    )
-  } // istanbul ignore next
-
-  return false
-}
-
 configureDTL({
   unstable_advanceTimersWrapper: cb => {
     // Only needed to support test environments that enable fake timers after modules are loaded.
@@ -44,21 +30,7 @@ configureDTL({
     const previousActEnvironment = getIsReactActEnvironment()
     setReactActEnvironment(false)
     try {
-      const result = await cb()
-      // Drain microtask queue.
-      // Otherwise we'll restore the previous act() environment, before we resolve the `waitFor` call.
-      // The caller would have no chance to wrap the in-flight Promises in `act()`
-      await new Promise(resolve => {
-        setTimeout(() => {
-          resolve()
-        }, 0)
-
-        if (jestFakeTimersAreEnabled()) {
-          jest.advanceTimersByTime(0)
-        }
-      })
-
-      return result
+      return await cb()
     } finally {
       setReactActEnvironment(previousActEnvironment)
     }