[ci] Shard playground tests

playwright also supports sharding tests. Let's see if we can get playground CI times down from 3-4 mins.

.github/workflows/compiler_playground.yml

@@ -23,8 +23,14 @@ defaults:
 
 jobs:
   playground:
-    name: Test playground
+    name: yarn test (Shard ${{ matrix.shard }})
     runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        shard:
+          - 1/3
+          - 2/3
+          - 3/3
     steps:
       - uses: actions/checkout@v4
       - uses: actions/setup-node@v4
@@ -38,13 +44,10 @@ jobs:
         with:
           path: "**/node_modules"
           key: compiler-node_modules-${{ runner.arch }}-${{ runner.os }}-${{ hashFiles('compiler/**/yarn.lock') }}
-      - name: yarn install compiler
-        run: yarn install --frozen-lockfile
-        working-directory: compiler
       - name: yarn install playground
         run: yarn install --frozen-lockfile
       - run: npx playwright install --with-deps chromium
-      - run: CI=true yarn test
+      - run: CI=true yarn test --shard=${{ matrix.shard }}
       - run: ls -R test-results
         if: '!cancelled()'
       - name: Archive test results