Add general warning for disabling the tests

Author: Thomas Kiley

regression/validate-trace-xml-schema/CMakeLists.txt

@@ -16,6 +16,7 @@ else()
   set_tests_properties(validate-trace-xml-schema
     PROPERTIES
     LABELS "CBMC;CORE")
+  message(WARNING "Dependencies for trace schema missing - tests will fail")
   if(NOT ${PYTHONINTERP_FOUND})
     message(WARNING "Python >= 3.5 not found, trace schema tests will fail")
   endif()