Suggestion: Allow output to be cleared before each test run

[mramsden]

It would be great if there was a way to have the output clear between each test run. The problem that I have found I have is being able to distinguish between two test executions and have found myself looking at the output from an older run. This is particularly apparent on smaller screens.

I've managed to configure my VS Code so that I can run with two sets of keyboard shortcuts so that I can clear the output and then run my test suite using yarn test.

Looking at the extension API documentation it is possible to call OutputChannel#clear before running.

Hiding this behind a configuration option would allow existing users to maintain the current behaviour of this functionality while allowing others to opt-in to the behaviour. I have taken a look at the plugin source and have an idea of how it would be possible to implement. Would you be open to a PR for this feature?