[gardening] Mark timing out tests as slow
[gardening] Mark timing out tests as slow

It seems that f99d3628d1e4e98df531fb9928bfb640783df59d
(CL https://dart-review.googlesource.com/33144)
caused these 5 tests to time out on the pkg builder as well as the try
bots.
Locally the tests take ~40 seconds, so giving it a bit more time (i.e.
marking them as slow) seems likely to turn things green again.

Bug:
Change-Id: I90526b1d7060309d8f1cf902bd9d52c71927f1ed
Reviewed-on: https://dart-review.googlesource.com/33340
Reviewed-by: Jens Johansen <05223a3c6bdf76af6f84755eae231abeebcf4530@google.com>
Reviewed-by: Dmitry Stefantsov <95a4b7e39916a54bd6477bec6a6de014b977db32@google.com>
Commit-Queue: Jens Johansen <05223a3c6bdf76af6f84755eae231abeebcf4530@google.com>

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