We currently store kunit suites in the .kunit_test_suites ELF section as
a `struct kunit_suite***` (modulo some `const`s).
For every test file, we store a struct kunit_suite** NULL-terminated array.

This adds quite a bit of complexity to the test filtering code in the
executor.

Instead, let's just make the .kunit_test_suites section contain a single
giant array of struct kunit_suite pointers, which can then be directly
manipulated. This array is not NULL-terminated, and so none of the test
filtering code needs to NULL-terminate anything.
Tested-by: NMaíra Canal <maira.canal@usp.br>
Reviewed-by: NBrendan Higgins <brendanhiggins@google.com>
Signed-off-by: NDaniel Latypov <dlatypov@google.com>
Co-developed-by: NDavid Gow <davidgow@google.com>
Signed-off-by: NDavid Gow <davidgow@google.com>
Signed-off-by: NShuah Khan <skhan@linuxfoundation.org>