Watcher tests - disable flaky test on Windows + Linux

Summary:
Despite increasing timeouts for this test a few times, we still see failures both in OSS and internal CI.

I'm pretty sure there's a race condition in both our own `FallbackWatcher` / `NodeWatcher` *and* Watchman where when recursively watching a subtree, new files are added before a directory is watched or crawled, and so we never see an event for them.

This is a problem, but I don't want to entirely lose the signal for this important set of tests due to that flakiness. This skips the problematic test on Windows and Linux until we have a better fix. We haven't observed a problem on macOS IIRC.

Changelog: Internal

Reviewed By: huntie

Differential Revision: D67712965

fbshipit-source-id: 2246d282f7edba8243a4e8922fea13137959cc3f

packages/metro-file-map/src/watchers/__tests__/integration-test.js

@@ -34,6 +34,8 @@ describe.each(Object.keys(WATCHERS))(
 
     // If all tests are skipped, Jest will not run before/after hooks either.
     const maybeTest = WATCHERS[watcherName] ? test : test.skip;
+    const maybeTestOn = (...platforms: $ReadOnlyArray<string>) =>
+      platforms.includes(os.platform()) ? test : test.skip;
 
     beforeAll(async () => {
       watchRoot = await createTempWatchRoot(watcherName);
@@ -233,7 +235,9 @@ describe.each(Object.keys(WATCHERS))(
       });
     });
 
-    maybeTest(
+    /* FIXME: Disabled on Windows and Darwin due to flakiness (occasional
+       timeouts) - see history. */
+    maybeTestOn('darwin')(
       'emits deletion for all files when a directory is deleted',
       async () => {
         await eventHelpers.allEvents(
@@ -267,8 +271,6 @@ describe.each(Object.keys(WATCHERS))(
           {rejectUnexpected: true},
         );
       },
-      // We see occasional failures in CI with default 5s timeout.
-      45000,
     );
   },
 );