To gradually remove illegal reflexive access operations from our code base, we need to be able to control the value of the --illegal-access option when running tests:

• Introduce a illegal.access property in the pom
• Set the default to deny so builds fail in the presence of illegal reflexive access operations
• Let individual project override the property when needed (i.e. setting it to debug will cause logging of stack traces).
• Ensure the option only applies when building on JDK9+