ci: build tetris with -usecache on linux

.github/workflows/ci.yml

@@ -233,8 +233,10 @@ jobs:
 #      run: ./v -freestanding -o bare vlib/os/bare/bare_example_linux.v
     - name: v self compilation
       run: ./v -o v2 cmd/v && ./v2 -o v3 cmd/v && ./v3 -o v4 cmd/v
-    - name: v self with -usecache
-      run: ./v -o v2 -usecache cmd/v
+    - name: -usecache
+      run: |
+		./v -o v2 -usecache cmd/v
+		./v -usecache examples/tetris/tetris.v
     - name: Fixed tests
       run: |
         ./v -silent test-fixed