ci: Add clang-tidy task

ci/test/00_setup_env.sh

@@ -37,6 +37,7 @@ export USE_BUSY_BOX=${USE_BUSY_BOX:-false}
 
 export RUN_UNIT_TESTS=${RUN_UNIT_TESTS:-true}
 export RUN_FUNCTIONAL_TESTS=${RUN_FUNCTIONAL_TESTS:-true}
+export RUN_TIDY=${RUN_TIDY:-false}
 export RUN_SECURITY_TESTS=${RUN_SECURITY_TESTS:-false}
 # By how much to scale the test_runner timeouts (option --timeout-factor).
 # This is needed because some ci machines have slow CPU or disk, so sanitizers