Enable direct tracing the autobuild build mode by default

[henrymercer]

Merge this once we've cut the final GHES 3.14 release.

This PR removes the feature flag for using direct tracing for the autobuild build mode, thereby enabling it for GHES.

Probably the most controversial change is removing the tests that require us to have at least one feature with a minimumVersion and toolsVersion property. I did this because if no features have a toolsVersion property, we'll never hit those code paths, so it isn't that important to test them. Having a synthetic feature is an option but might create user confusion.

Merge / deployment checklist

• [ ] Confirm this change is backwards compatible with existing workflows.
• [ ] Confirm the readme has been updated if necessary.
• [ ] Confirm the changelog has been updated if necessary.