Tests should (optionally) fail if container env not available

[jasondlee]

Add sys prop check to determine whether to fail hard

[jamezp]

ha, I just left a comment on the issue, but maybe we could have an option to have a system property like org.arquillian.testcontainers.required.exception=java.lang.AssertionError and allow the type to be overridden.

[jasondlee]

@rhusar @jamezp I have updated the PR with the code to allow a sysprop override of the exception. Please review and provide feedback...

[rhusar]

I prefer the deleting approach. But OK as a temporary fix.

[rhusar]

@jamezp gets the final say :-)