Fix conformance suite logic for reading SupportedFeatures from Status

[bexxmodd]

What happened:
There were couple of issue discovered when attempted to run conformance tests manually:

1. --all-features and --exempt-features didn't work together.
2. When asked for Mesh profile and Marked Gateway as exempt, Gateway tests were still run.

What you expected to happen:

1. when --all-features and --exempt-features are specified, tests should be run for all tests except the exempt ones.
2. Gateway tests should not run