* test: Migrate TrackedSpec.scala to verify.BasicTestSuite
Migrate TrackedSpec.scala from ScalaTest's AnyFlatSpec to
verify.BasicTestSuite, following the pattern established by other
test files in the sbt codebase.
Changes:
- Replace AnyFlatSpec class with BasicTestSuite object
- Convert 'should ... in' syntax to 'test(...)' syntax
- Use Scala 3 syntax with colon indentation
- Change === to == for assertions (BasicTestSuite style)
- Replace fail() with throw new AssertionError for explicit failures
- Add 'end TrackedSpec' marker
- Convert braces to colon-style for if expressions
The input validation for caching currently relies on having a stack of `scala.math.Equiv`, which is questionable since it can fallback to universal equality.
This is likely related to the intermittent caching behavior we are seeing in https://github.com/sbt/sbt/issues/3226
sbt/util#45 implemented caching using sjson-new. Now many of the functions take `CacheStore` that abstracts the caching ability.
sbt/sbt#3109 demonstrates that setting up CacheStore requires boilerplate involving concepts introduced in sbt 1.
This change adds back overrides using File by making assumption that majority of the time we would want standard JSON converter.