fwts_test.py needs test validation

[Jeff Lane ]

fwts presents different tests for different architectures. currently, when running fwts on power, for example, we get a whole lot of failures because a requested test isn't available in the power version of fwts.

For this reason, we need test validation of requested tests to only run the tests that apply to the given arch.

This is possible by doing a --show-tests to get all tests available (FWTS will only return tests available for the detected arch, thus --show-tests on power will be different than on amd64 will be different than on arm64 and so forth.

So we need to compare the tests we want to run against what FWTS says it can run, then run the tests that FWTS has that we want, and mark the rest as skipped and don't bother running them.