Revert "kunit: memcpy: Split slow memcpy tests into MEMCPY_SLOW_KUNIT_TEST"

Revert "kunit: memcpy: Split slow memcpy tests into MEMCPY_SLOW_KUNIT_TEST"

This reverts commit 4acf1de35f41549e60c3c02a8defa7cb95eabdf2.

Commit d055c6a2cc16 ("kunit: memcpy: Mark tests as slow using test
attributes") marks slow memcpy unit tests as slow. Since this commit,
the tests can be disabled with a module parameter, and the configuration
option to skip the slow tests is no longer needed. Revert the patch
introducing it.

Cc: David Gow <davidgow@google.com>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20240314151200.2285314-1-linux@roeck-us.net
Signed-off-by: Kees Cook <keescook@chromium.org>