Temporarily disable tiler windows tests

[LongCatIsLooong]

Pre-launch Checklist

• I read the Contributor Guide and followed the process outlined there for submitting PRs.
• I read the Tree Hygiene wiki page, which explains my responsibilities.
• I read the Flutter Style Guide recently, and have followed its advice.
• I signed the CLA.
• I listed at least one issue that this PR fixes in the description above.
• I updated/added relevant documentation (doc comments with ///).
• I added new tests to check the change I am making, or this PR is test-exempt.
• All existing and new tests are passing.

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[yaakovschectman]

Can you explain what exactly happened that caused the failure and what will let you reenable the test?

[LongCatIsLooong]

Right now the default font is controlled by whether an env variable is present (USE_FLUTTER_TEST_FONT).

The tests in this repo were passing because I added the env var to the CI configuration but i didn't realize the env var won't be present when flutter/flutter runs these test. I couldn't find a way to set the env variable on windows in a *.test file so I think it's easier/quicker to disable the tests on windows temporarily. Once flutter/engine#40352 lands the failure should go away (since the flutter/test CI is passing) and I'll re-enable those tests.

[yaakovschectman]

LGTM but probably need to see what Hixie says

[LongCatIsLooong]

I'm taking Hixie's response on discord as a LGTM.

[auto-submit]

auto label is removed for flutter/tests, pr: 235, due to - The status or check suite tests-windows-0 has failed. Please fix the issues identified (or deflake) before re-applying this label.