[gardening] Skip timing out bigint tests on slow configurations (#31659)
[gardening] Skip timing out bigint tests on slow configurations (#31659)

Change-Id: Icae0660dead53848f46ed19bdf1a4f465bec944e
Reviewed-on: https://dart-review.googlesource.com/c/78520
Reviewed-by: William Hesse <a821cddceae7dc400f272e3cb1a72f400f9fed6d@google.com>

dartino/dart-sdk,dart-archive/dart-sdk,dartino/dart-sdk,dart-lang/sdk,dart-lang/sdk,dart-archive/dart-sdk,dart-lang/sdk,dartino/dart-sdk,dartino/dart-sdk,dart-archive/dart-sdk,dart-archive/dart-sdk,dart-archive/dart-sdk,dart-archive/dart-sdk,dart-archive/dart-sdk,dartino/dart-sdk,dart-archive/dart-sdk,dartino/dart-sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dartino/dart-sdk,dartino/dart-sdk,dart-archive/dart-sdk,dart-lang/sdk,dartino/dart-sdk