Add WEBOTS_HOME to PATH before running tests.

.github/workflows/test_suite_windows.yml

@@ -139,6 +139,7 @@ jobs:
         python scripts/packaging/update_urls.py $(git log -1 --format='%H')
         export TESTS_HOME=$PWD # required by cache group in the test suite
         export WEBOTS_HOME="/c/Program Files/Webots"
+        export PATH="${WEBOTS_HOME}:${WEBOTS_HOME}/bin:$PATH"
         export WEBOTS_HOME_PATH=$PWD # required for tests to find Makefile.include
         export BRANCH_HASH=$(git log -1 --format='%H')
         python tests/test_suite.py