Remove useless tests from `Tests_Basic`

[Frank Klein]

The Tests_Basic class contains several tests, which do not seem to be testing anything useful:

• test_globals() and test_globals_bar(): The bug in question has been fixed for a long time, plus issues with PHPUnit should be handled upstream.
• test_setting_nonexistent_arrays(), test_magic_getter(), test_subclass_magic_getter(), test_call_method(), test_subclass_magic_getter(), test_call_method(), test_subclass_call_method(), test_subclass_isset(), and test_subclass_unset() all needlessly test basic PHP features.
• _switch_order_helper() is unused, except in it's test_switch_order() test, and since Tests_Basic is a test class, it can be removed.

Some of these tests have been added for HHVM support, but are no longer needed after this support was removed as part of #40548.

[johnbillion]

In 42381:

Build/Test tools: Remove unnecessary PHP functionality tests from the test suite.

Props Frank Klein
Fixes #42277

[TimothyBlynJacobs]

Why were the basic object classes removed? See #37523

[Frank Klein]

@TimothyBlynJacobs They were removed because they do not actually test anything, besides normal PHP behaviour.

Is there a use case for the WordPress Core tests that was missed?

[TimothyBlynJacobs]

Because they are helpful objects when writing tests with the WP test lib. I don't see any issue with removing the unnecessary PHP functionality tests, but I don't see why the basic object classes themselves were removed.

[Frank Klein]

They were removed because Core does not need them anymore. In my view there's enough outstanding work on tests that we should not continue to invest resources into code that is no longer needed.

Consider including these classes in your own testing setup if you find them useful.

[johnbillion]

Yeah this is a real edge case and we have more pressing issues to deal with. I'd recommend implementing these classes in your own test suite.