Add --codegen-debug for tests

[DomBlack]

This commit adds the ability for us to use --codegen-debug to export the support code used by encore test. (Similar to how we have encore check --codegen-debug for the application itself)

[encore-cla]

All committers have signed the CLA.

[github-actions]

Test Results

    2 files  +       1  219 suites  +64   7m 36s ⏱️ - 4m 55s
714 tests +   163  711 ✔️ +   171  3 💤 +3  0 ❌  - 3 
714 runs   - 1 881  711 ✔️  - 1 873  3 💤 +3  0 ❌  - 3 

Results for commit f981d4a. ± Comparison against base commit 44b23c8.

This pull request removes 38 and adds 201 tests. Note that renamed tests count towards both.

encr.dev/e2e-tests ‑ TestRun/encore_currentrequest
encr.dev/e2e-tests ‑ TestRun/et_override_user
encr.dev/e2e-tests ‑ TestRun/et_override_user_authdata
encr.dev/e2e-tests ‑ TestRun/experiment_local_secrets_override
encr.dev/e2e-tests ‑ TestRun/fallback_routes
encr.dev/e2e-tests ‑ TestRun/pubsub_method_handler
encr.dev/e2e-tests ‑ TestRun/pubsub_ref
test/svc ‑ TestEndToEndWithApp
test/svc ‑ TestEndToEndWithApp/basic_requests
test/svc ‑ TestEndToEndWithApp/basic_requests/POST_and_GET
…

encore.dev/appruntime/apisdk/api ‑ TestDescGeneratesTrace
encore.dev/appruntime/apisdk/api ‑ TestDescGeneratesTrace/echo
encore.dev/appruntime/apisdk/api ‑ TestDescGeneratesTrace/invalid
encore.dev/appruntime/apisdk/api ‑ TestDescGeneratesTrace/raw
encore.dev/appruntime/apisdk/api ‑ TestDescGeneratesTrace/unauthenticated
encore.dev/appruntime/apisdk/api ‑ TestDesc_EndToEnd
encore.dev/appruntime/apisdk/api ‑ TestDesc_EndToEnd/echo
encore.dev/appruntime/apisdk/api ‑ TestDesc_EndToEnd/invalid
encore.dev/appruntime/apisdk/api ‑ TestDesc_EndToEnd/unauthenticated
encore.dev/appruntime/apisdk/api ‑ TestRawEndpointOverflow
…