updated docs to remove note about windows tests not working (#13650)

* updated docs to remove note about windows tests not working

* reverted formatting

CONTRIBUTING.md

@@ -95,8 +95,6 @@ assume you want to check a single package and the flutter repository has several
 Running the tests
 -----------------
 
-_The `flutter test` command is not available on Windows (See [#8516](https://github.com/flutter/flutter/issues/8516))._
-
 To automatically find all files named `_test.dart` inside a package's `test/` subdirectory, and run them inside the flutter shell as a test, use the `flutter test` command, e.g:
 
  * `cd examples/stocks`