feat(testing): explicit resource management for spy() and stub()

[KyleJune]

Closes #3966

This is a work in progress. It won't work until swc is upgraded to v1.4.0 because earlier versions do not support the using keyword on functions. Until that issue is resolved, the new test cases I added fail with the following errors.

Once that issue is resolved, I believe the new test cases in this PR will pass and we could go forward with shipping it.

Regarding documentation, I added a description to both the spy and stub sections to explain that they are disposable. I noticed that FakeTime was already made disposible and it's example uses the using keyword. I thought it would be better to explicitly explain that since using is a new feature to TypeScript. I think if all the examples were updated to just use the using keyword to automate cleanup, people could easily miss the importance of that keyword in ensuring that the tests are cleaned up properly. Feel free to change my descriptions though.

[iuioiua]

Note to self: run CI when the required functionality is available in canary. Tests should pass in canary but fail in stable.

[iuioiua]

Note to self: run CI when the required functionality is available in canary. Tests should pass in canary but fail in stable.

I didn't notice, but this is already the case! 😆 We've already upgraded to swc@1.4.0. I'll review this in time for the next release of deno_std.

[iuioiua]

@KyleJune, would you also like to update any applicable spies and stubs across the codebase to use the using keyword, too?

[babiabeo]

I think we should also add a note about the minimum Deno version required for it to work. 👍

[KyleJune]

@KyleJune, would you also like to update any applicable spies and stubs across the codebase to use the using keyword, too?

Done, the only ones outside of the context of testing testing/mock_test.ts and testing/time_test.ts were testing/bdd_test.ts and http/file_server_test.ts. I didn't update the mock and time tests since the restore abilities are part of what is being tested.

I think we should also add a note about the minimum Deno version required for it to work. 👍

I don't think that is necessary and that wasn't done when FakeTime was updated to have explicit resource management. I don't know if the next version will be v1.40.5 or v1.41.0 so I'm not going to update it to say which version is required. If the core members want to update it to specify the minimum version required for it, they can make the change.

[babiabeo]

I think this PR is now ready to be reviewed as Deno v1.40.5 supports using with function.

[kt3k]

LGTM. Looks a nice feature!

[iuioiua]

This is awesome. Thank you! LGTM.