Speed up playwright runs by sharding using tenbin

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

.github/workflows/end-to-end-tests.yaml

@@ -164,13 +164,25 @@ jobs:
               if: matrix.project == 'WebKit' && steps.playwright-cache.outputs.cache-hit == 'true'
               run: yarn playwright install-deps webkit
 
+            # Restore test-results.json file, which records the execution time of each test file.
+            # splitTests function uses this file for sharding.
+            - name: Restore playwright-results.json
+              uses: actions/cache/restore@v4
+              with:
+                  path: playwright-results.json
+                  key: playwright-results-${{ github.ref_name }}
+                  restore-keys: |
+                      playwright-results-${{ github.base_ref }}
+                      playwright-results-develop
+
             # We skip tests tagged with @mergequeue when running on PRs, but run them in MQ and everywhere else
             - name: Run Playwright tests
               run: |
                   yarn playwright test \
-                      --shard "${{ matrix.runner }}/${{ needs.build.outputs.num-runners }}" \
                       --project="${{ matrix.project }}" \
                       ${{ (github.event_name == 'pull_request' && matrix.runAllTests == false ) && '--grep-invert @mergequeue' || '' }}
+              env:
+                  SHARD: "${{ matrix.runner }}/${{ needs.build.outputs.num-runners }}"
 
             - name: Upload blob report to GitHub Actions Artifacts
               if: always()
@@ -212,10 +224,17 @@ jobs:
 
             - name: Merge into HTML Report
               if: inputs.skip != true
-              run: yarn playwright merge-reports --reporter=html,./playwright/flaky-reporter.ts,./playwright/stale-screenshot-reporter.ts ./all-blob-reports
+              run: yarn playwright merge-reports --reporter=html,json,./playwright/flaky-reporter.ts,./playwright/stale-screenshot-reporter.ts ./all-blob-reports
               env:
                   # Only pass creds to the flaky-reporter on main branch runs
                   GITHUB_TOKEN: ${{ github.ref_name == 'develop' && secrets.ELEMENT_BOT_TOKEN || '' }}
+                  PLAYWRIGHT_JSON_OUTPUT_NAME: playwright-results.json
+
+            - name: Cache playwright-results.json
+              uses: actions/cache/save@v4
+              with:
+                  path: playwright-results.json
+                  key: playwright-results-${{ github.ref_name }}
 
             # Upload the HTML report even if one of our reporters fails, this can happen when stale screenshots are detected
             - name: Upload HTML report