Add tests for `org.beeware.ARGV` and `org.beeware.ENVIRON`

[timrid]

What is the problem or limitation you are having?

Currently the command line arguments (passed to an android app via org.beeware.ARGV) and environment variables (passed to an android app via org.beeware.ENVIRON as proposed here ) are not automatically tested for android.

Describe the solution you'd like

The command line arguments and environment variables should be automatically tested.

Describe alternatives you've considered

Do not test these cases automatically. Manual testing is enough.

Additional context

This has been proposed here: beeware/briefcase-android-gradle-template#97 (comment)

[freakboy3742]

Agreed this would be potentially useful - but it shouldn't be Android specific - we should be checking argument passing and environment variables on every platform.