[Code cleanup] Component iteration in test runners

[kavilla]

Is your feature request related to a problem? Please describe

Clean up the logic for test runners that go through the components. [EXAMPLE]

Source: #1603 (comment)

Not for this PR, but we do a similar workflow in many places and I don't love the double-select here, first pass --component name to pick a component, but then we also only want components that have a test configuration.

Describe the solution you'd like

Source: #1603 (comment)

One option would be to fail if self.args.component not in self.test_manifest.components with an explicit error, and refactor components.select to take an array of components, i.e. self.components.select(focus=self.test_manifest.components).

Another, possibly better, could be to do self.components.select(focus=self.args.component, configs=self.test_manifest.components, key: "bwc_test") that would return a set of tuples of component + configuration. The code then becomes quite clean:

for component, config in self.components.select(focus=self.args.component, configs: self.test_manifest.components, key: "bwc_test"):
   test_suite = ...
   ...

Describe alternatives you've considered

N/A

Additional context

No response

[kavilla]

More clean up: #1512. Type new classes.

[gaiksaya]

Closing this issue as stale. Don't see any action item in the PR description. Please re-open if needed.