(add) add test262 workflow

.github/workflows/test262.yml

@@ -0,0 +1,20 @@
+name: Testing
+on: push
+
+steps:
+  - uses: actions/checkout@v4
+  - name: Cache nimble
+    id: cache-nimble
+    uses: actions/cache@v4
+    with:
+      path: ~/.nimble
+      key: ${{ runner.os }}-nimble-${{ hashFiles('*.nimble') }}
+      restore-keys: |
+        ${{ runner.os }}-nimble-
+  - uses: jiro4989/setup-nim-action@v2
+    with:
+      nim-version: '2.2.0'
+      repo-token: ${{ secrets.GITHUB_TOKEN }}
+  - run: nimble build --define:release
+  - run: git clone https://github.com/tc39/test262.git
+  - run: ./bin/test262 run-all-tests-rec .