[deps] rev test

Revisions updated by `dart tools/rev_sdk_deps.dart`.

test (https://github.com/dart-lang/test/compare/5aef971..b99d556):
  b99d556  2025-09-01  dependabot[bot]  Bump the github-actions group across 1 directory with 3 updates (dart-lang/test#2534)
  abe4939b  2025-08-27  Nate Bosch  Remove executable argument forwarding in tests (dart-lang/test#2533)
  81e0579c  2025-08-26  Ömer Sinan Ağacan  Serve dart2wasm source map files (dart-lang/test#2532)
  9354f239  2025-08-07  Liam Appelbe  Add `--coverage-path` and `--branch-coverage` options (dart-lang/test#2517)

Change-Id: I7297cc534d03de343218c829a8e94d70ba35a023
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/448423
Auto-Submit: Devon Carew <[email protected]>
Reviewed-by: Konstantin Shcheglov <[email protected]>
Commit-Queue: Konstantin Shcheglov <[email protected]>

Author: devoncarew

DEPS

@@ -146,7 +146,7 @@ vars = {
   "shelf_rev": "de91a5b8c1de05f622c0c6f1eab38d5f31e0113f",
   "sync_http_rev": "6666fff944221891182e1f80bf56569338164d72",
   "tar_rev": "d511a1dc4f197a29bc06479f4614135abb168b6e",
-  "test_rev": "5aef9719ad9b598260c062b2a90a50d2f50a78f3", # https://dart-review.googlesource.com/c/sdk/+/444360
+  "test_rev": "b99d556ec6096965eb177111299c0783678200f6",
   "tools_rev": "24707e094cd761178eb76e725ce17f51e22fd442",
   "vector_math_rev": "3939545edc38ed657381381d33acde02c49ff827",
   "web_rev": "a15205456e2dd9f6d5b3a28d600a77d792ccf24d",