tools: add a check for clean git tree after tests

Signed-off-by: Antoine du Hamel <duhamelantoine1995@gmail.com>

Author: aduh95

.github/workflows/test-linux.yml

@@ -80,6 +80,8 @@ jobs:
         run: make -C node build-ci -j4 V=1 CONFIG_FLAGS="--error-on-warn --v8-enable-temporal-support"
       - name: Test
         run: make -C node test-ci -j1 V=1 TEST_CI_ARGS="-p actions --measure-flakiness 9"
+      - name: Ensure running tests did not cause any change in the tree
+        run: cd node && git diff --name-only --exit-code
       - name: Re-run test in a folder whose name contains unusual chars
         run: |
           mv node "$DIR"