feat(runtime): implement jstz_test ext

[johnyob]

Context

This PR implements functionality in the Jstz runtime to add support for registering test specifications.

The API is identical to Deno.test (https://docs.deno.com/runtime/fundamentals/testing/)

Description

This PR copies and pastes code directly from https://github.com/denoland/deno/tree/main/cli/tools/test
and https://github.com/denoland/deno/tree/main/cli/js.

When reviewing this PR, one can ignore:

• 40_test_common.js -- this is a copy of https://github.com/denoland/deno/blob/main/cli/js/40_test_common.js
• 40_test.js -- this is a copy of https://github.com/denoland/deno/blob/main/cli/js/40_test.js

Most of the types and functions in jstz_test/mod.rs are taken from various files in https://github.com/denoland/deno/tree/main/cli/tools/test.

Manually testing the PR

This PR comes with a unit test to check that we correctly register the extension and that test specs are visible in Rust once the main module has been evaluated.

cargo test --package jstz_runtime --lib --features v2_runtime -- ext::jstz_test::tests

[codecov]

Codecov Report

❌ Patch coverage is 34.90909% with 179 lines in your changes missing coverage. Please review.
✅ Project coverage is 63.93%. Comparing base (dc6aab6) to head (a2c945d).

Files with missing lines	Patch %	Lines
crates/jstz_runtime/src/ext/jstz_test/mod.rs	34.90%	179 Missing ⚠️

Files with missing lines	Coverage Δ
crates/jstz_runtime/src/ext/mod.rs	0.00% <ø> (ø)
crates/jstz_runtime/src/lib.rs	16.66% <ø> (ø)
crates/jstz_runtime/src/ext/jstz_test/mod.rs	34.90% <34.90%> (ø)

... and 1 file with indirect coverage changes

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[zcabter]

Suggested change

	pub mod jstz_test;
	pub mod jstz_test;

Can we remove the empty lines?

[zcabter]

Do these js files have accompanying .d.ts files?

[zcabter]

Could you also create Linear issues and attach them to Jstz.Test framework for project level tracking?

[zcabter]

That's odd... Doesn't JstzRuntime automatically drop when it goes out of scope on line 582?

[zcabter]

What does this do?

[zcabter]

Its probably a good idea to document the general ADT architecture either on top of each struct or as an overview here for future maintainers to get a better mental model of the data structure