NativeIO: Add timeout=long to flaky web platform tests

This CL adds longer timeouts to some WPT that occasionally time out
under macOS. I expect this will reduce the flakiness for tests that
spend a long time accessing the hard drive.

Bug: 1157915
Change-Id: I5fc3e4716dec5a9d0c17021bf02e449b5dda400d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2587164
Commit-Queue: Richard Stotz <rstz@chromium.org>
Reviewed-by: Victor Costan <pwnall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#836616}

third_party/blink/web_tests/external/wpt/native-io/close_async.tentative.https.any.js

 // META: title=NativeIO API: close().
 // META: global=window,worker
 // META: script=resources/support.js
+// META: timeout=long
 
 'use strict';
 

third_party/blink/web_tests/external/wpt/native-io/concurrent_io/concurrent_io_read_async.tentative.https.any.js

@@ -2,6 +2,7 @@
 // META: global=window,worker
 // META: script=operation_helpers.js
 // META: script=../resources/support.js
+// META: timeout=long
 
 'use strict';
 

third_party/blink/web_tests/external/wpt/native-io/concurrent_io/concurrent_io_setLength_async.tentative.https.any.js

@@ -2,6 +2,7 @@
 // META: global=window,worker
 // META: script=operation_helpers.js
 // META: script=../resources/support.js
+// META: timeout=long
 
 'use strict';
 

third_party/blink/web_tests/external/wpt/native-io/concurrent_io/concurrent_io_write_async.tentative.https.any.js

@@ -2,6 +2,7 @@
 // META: global=window,worker
 // META: script=operation_helpers.js
 // META: script=../resources/support.js
+// META: timeout=long
 
 'use strict';
 

third_party/blink/web_tests/external/wpt/native-io/flush_async_basic.tentative.https.any.js

 // META: title=Synchronous NativeIO API: Flushed data is read back.
 // META: global=window,worker
 // META: script=resources/support.js
+// META: timeout=long
 
 'use strict';
 

third_party/blink/web_tests/external/wpt/native-io/rename_async_failure_handling.tentative.https.any.js

 // META: title=NativeIO API: Failures of rename are properly handled.
 // META: global=window,worker
 // META: script=resources/support.js
+// META: timeout=long
 
 'use strict';