chore: add page snapshot on test end

[Skn0tt]

Adds a pageSnapshot option that allows testserver clients to get an ARIA snapshot at the end of the test. It works just like the existing screenshot logic, so I extracted that to reuse it.

[github-actions]

Test results for "tests 1"

1 failed
❌ [webkit-library] › tests/library/video.spec.ts:441:5 › screencast › should work for popups @webkit-ubuntu-22.04-node18

18 flaky

⚠️ [firefox-library] › tests/library/inspector/cli-codegen-pick-locator.spec.ts:35:7 › should update locator highlight @firefox-ubuntu-22.04-node18
⚠️ [firefox-page] › tests/page/page-evaluate.spec.ts:403:3 › should throw for too deep reference chain @firefox-ubuntu-22.04-node18
⚠️ [webkit-library] › tests/library/browsercontext-clearcookies.spec.ts:72:3 › should remove cookies by name regex @webkit-ubuntu-22.04-node18
⚠️ [webkit-library] › tests/library/browsercontext-clearcookies.spec.ts:92:3 › should remove cookies by domain @webkit-ubuntu-22.04-node18
⚠️ [webkit-library] › tests/library/browsercontext-har.spec.ts:415:3 › should ignore boundary when matching multipart/form-data body @webkit-ubuntu-22.04-node18
⚠️ [webkit-library] › tests/library/browsercontext-reuse.spec.ts:50:1 › should reset serviceworker @webkit-ubuntu-22.04-node18
⚠️ [webkit-library] › tests/library/browsercontext-viewport-mobile.spec.ts:87:5 › mobile viewport › should support window.orientation emulation @webkit-ubuntu-22.04-node18
⚠️ [webkit-library] › tests/library/browsercontext-viewport-mobile.spec.ts:97:5 › mobile viewport › should fire orientationchange event @webkit-ubuntu-22.04-node18
⚠️ [webkit-library] › tests/library/defaultbrowsercontext-2.spec.ts:28:3 › should work in persistent context @webkit-ubuntu-22.04-node18
⚠️ [webkit-library] › tests/library/popup.spec.ts:129:3 › should use viewport size from window features @webkit-ubuntu-22.04-node18
⚠️ [webkit-library] › tests/library/screenshot.spec.ts:44:14 › page screenshot › should work with a mobile viewport @webkit-ubuntu-22.04-node18
⚠️ [webkit-library] › tests/library/screenshot.spec.ts:206:14 › element screenshot › element screenshot should work with a mobile viewport @webkit-ubuntu-22.04-node18
⚠️ [webkit-library] › tests/library/screenshot.spec.ts:278:14 › element screenshot › should restore viewport after page screenshot and exception @webkit-ubuntu-22.04-node18
⚠️ [webkit-library] › tests/library/screenshot.spec.ts:291:14 › element screenshot › should restore viewport after page screenshot and timeout @webkit-ubuntu-22.04-node18
⚠️ [webkit-library] › tests/library/video.spec.ts:411:5 › screencast › should capture css transformation @webkit-ubuntu-22.04-node18
⚠️ [webkit-page] › tests/page/page-leaks.spec.ts:107:5 › fill should not leak @webkit-ubuntu-22.04-node18
⚠️ [webkit-page] › tests/page/page-set-input-files.spec.ts:147:3 › should upload large file @webkit-ubuntu-22.04-node18
⚠️ [playwright-test] › tests/ui-mode-test-watch.spec.ts:145:5 › should watch all @windows-latest-node18-1

37734 passed, 654 skipped
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Merge workflow run.