Increase FileSystemWatcher test event timeout to 1000ms

[lewing]

Increase WaitForExpectedEventTimeout from 500ms to 1000ms per @tmds suggestion in #125740 (comment).

The inotify refactor (#117148) changed stop/start timing for watches, which can delay event delivery under stress conditions. The 500ms timeout is too tight for jitstress runs on slower hardware (arm32), causing false failures in SymbolicLink tests that are being incorrectly attributed to #103630.

This is a single constant change that affects 94 tests using the default ExpectEvent timeout. It should help distinguish timing issues from functional bugs.

Ref: #125737, #125740

/cc @tmds @adamsitnik @jozkee

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[Copilot]

Pull request overview

This PR increases the default wait timeout used by FileSystemWatcher test utilities to reduce Linux (notably arm32 jitstress) timing-related flakiness after the inotify refactor.

Changes:

• Increase WaitForExpectedEventTimeout from 500ms to 1000ms in the FileSystemWatcher test base helper.

Comments suppressed due to low confidence (1)

src/libraries/System.IO.FileSystem.Watcher/tests/Utility/FileSystemWatcherTest.cs:28

• Raising WaitForExpectedEventTimeout will also increase the default wait for negative assertions and fixed sleeps that use this constant (e.g., ExpectNoEvent has a default timeout = WaitForExpectedEventTimeout, and some tests call Thread.Sleep(WaitForExpectedEventTimeout)). That can add ~500ms per such call to successful test runs. Consider keeping WaitForExpectedEventTimeout scoped to expected events only (e.g., change ExpectNoEvent’s default to WaitForUnexpectedEventTimeout, or introduce a separate constant for the longer expected-event wait) so the flakiness fix doesn’t unnecessarily slow the suite.

        public const int WaitForExpectedEventTimeout = 1000;         // ms to wait for an event to happen
        public const int LongWaitTimeout = 50000;                   // ms to wait for an event that takes a longer time than the average operation
        public const int SubsequentExpectedWait = 10;               // ms to wait for checks that occur after the first.
        public const int WaitForExpectedEventTimeout_NoRetry = 3000;// ms to wait for an event that isn't surrounded by a retry.
        public const int WaitForUnexpectedEventTimeout = 150;       // ms to wait for a non-expected event.

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[adamsitnik]

LGTM, big thanks for fixing it @lewing !

[lewing]

/ba-g failures are infrastructure and actively being resolved