ci: add a step in misc-tooling, to ensure v -autofree -o v2 cmd/v does not regress

.github/workflows/ci.yml

@@ -116,7 +116,8 @@ jobs:
           sudo apt-get install --quiet -y xfonts-75dpi xfonts-base
       - name: Build v
         run: make
-      - name: ensure v up works
+        
+      - name: Ensure v up works
         run: |
           ./v cmd/tools/oldv.v
           ./cmd/tools/oldv -v HEAD^^^^^
@@ -126,6 +127,10 @@ jobs:
           ./v version
           ./v  -o v2 cmd/v
           ./v2 -o v3 cmd/v
+      
+      - name: Ensure V can be compiled with -autofree
+        run: ./v -autofree -o v2 cmd/v  ## NB: this does not mean it runs, but at least keeps it from regressing
+        
       - name: Shader examples can be build
         run: |
           wget https://github.com/floooh/sokol-tools-bin/archive/pre-feb2021-api-changes.tar.gz