dillon1000/react

[tests] remove jest fixture tests

--- 

Remove jest fixture tests in favor of snap runner. Main reasons: 

- maintaining feature flags and compatible behavior required syncing all changes 
to 3 files (`generateTestsFromFixtures`, `compiler-test`, and `compiler-worker`) 

- jest snapshot test file causes rebase conflicts on most rebases 

- speed 🙌 

$ time yarn test compiler-test 

(the extra test here is `has a consistent extension for input fixtures`) 

``` 

Test Suites: 1 passed, 1 total 

Tests:       37 skipped, 480 passed, 517 total 

Snapshots:   479 passed, 479 total 

Time:        27.668 s 

Ran all test suites matching /compiler-test/i. 

✨  Done in 43.18s. 

yarn test compiler-test  57.05s user 3.85s system 139% cpu 43.546 total 

``` 

$ time yarn snap 

``` 

478 Tests, 478 Passed, 0 Failed 

✨  Done in 13.12s. 

yarn snap  53.96s user 9.35s system 468% cpu 13.518 total 

``` 

Jest and snap should have the same set of features: 

- report test failures via exit status (used by Git Actions) 

- watch mode 

- breakpoints + `debugger` statements 

- note that `--sync` is not required for this 

- skip `todo.` prefixed fixtures 

- fixtures in nested directories e.g. `rules-of-hooks/testname.js` 

- filter mode (via editing `testfilter.txt`) 

- filter + debug mode 

(1) edit `testfilter.txt` to filter out all but one test 

(2) add `@debug` pragma to the first line of the test 

testfilter.txt 

```js 

// @only 

testfixture_basename1 

testfixture_basename2 

```