Codemod act -> await act (4/?)

Similar to the rationale for `waitFor` (see facebook#26285), we should always
await the result of an `act` call so that microtasks have a chance to
fire.

This only affects the internal `act` that we use in our repo, for now.
In the public `act` API, we don't yet require this; however, we
effectively will for any update that triggers suspense once `use` lands.
So we likely will start warning in an upcoming minor.

Author: acdlite

packages/react-reconciler/src/__tests__/ReactHooks-test.internal.js

@@ -32,8 +32,8 @@ describe('ReactOffscreenStrictMode', () => {
   }
 
   // @gate __DEV__ && enableOffscreen
-  it('should trigger strict effects when offscreen is visible', () => {
-    act(() => {
+  it('should trigger strict effects when offscreen is visible', async () => {
+    await act(async () => {
       ReactNoop.render(
         <React.StrictMode>
           <Offscreen mode="visible">
@@ -56,8 +56,8 @@ describe('ReactOffscreenStrictMode', () => {
   });
 
   // @gate __DEV__ && enableOffscreen && useModernStrictMode
-  it('should not trigger strict effects when offscreen is hidden', () => {
-    act(() => {
+  it('should not trigger strict effects when offscreen is hidden', async () => {
+    await act(async () => {
       ReactNoop.render(
         <React.StrictMode>
           <Offscreen mode="hidden">
@@ -71,7 +71,7 @@ describe('ReactOffscreenStrictMode', () => {
 
     log = [];
 
-    act(() => {
+    await act(async () => {
       ReactNoop.render(
         <React.StrictMode>
           <Offscreen mode="hidden">
@@ -86,7 +86,7 @@ describe('ReactOffscreenStrictMode', () => {
 
     log = [];
 
-    act(() => {
+    await act(async () => {
       ReactNoop.render(
         <React.StrictMode>
           <Offscreen mode="visible">
@@ -109,7 +109,7 @@ describe('ReactOffscreenStrictMode', () => {
 
     log = [];
 
-    act(() => {
+    await act(async () => {
       ReactNoop.render(
         <React.StrictMode>
           <Offscreen mode="hidden">
@@ -127,7 +127,7 @@ describe('ReactOffscreenStrictMode', () => {
     ]);
   });
 
-  it('should not cause infinite render loop when StrictMode is used with Suspense and synchronous set states', () => {
+  it('should not cause infinite render loop when StrictMode is used with Suspense and synchronous set states', async () => {
     // This is a regression test, see https://github.com/facebook/react/pull/25179 for more details.
     function App() {
       const [state, setState] = React.useState(false);
@@ -143,7 +143,7 @@ describe('ReactOffscreenStrictMode', () => {
       return state;
     }
 
-    act(() => {
+    await act(async () => {
       ReactNoop.render(
         <React.StrictMode>
           <React.Suspense>
@@ -193,7 +193,7 @@ describe('ReactOffscreenStrictMode', () => {
       return null;
     }
 
-    act(() => {
+    await act(async () => {
       ReactNoop.render(
         <React.StrictMode>
           <Offscreen mode="visible">