Most of the fields in the query are not needed and are discarded
soon after visibility checks are made.

We are disabling the -v (verbose) option, used by default. Still,
now we support a secret (that can be added to everyone's repository)
to accept any PHPUnit's command line options and run the tests with
them.

Some examples:

phpunit_options = -v (to keep the verbose option enabled)
phpunit_options = --testdox (to print information about every test...)

... (basically anything supported by the CLI).

Also, we are raising here the environment from Ubuntu 18.04 to 20.04

(self tested by GHA, heh)

Switch the select element event listener to that provided by custom
events helper, for adding report filters and conditions. This improves
cross-platform support.