test: skip Azure Functions tests on Windows

[trentm]

This is because the 'azure-function-core-tools' package install on
Windows is too flaky in CI.

Closes: #3107

---

This implements option 1 described in #3107.

[ghost]

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• Start Time: 2023-01-24T22:14:24.072+0000

• Duration: 25 min 24 sec

Test stats 🧪

Test	Results
Failed	0
Passed	323266
Skipped	0
Total	323266

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