test: remove obsolete util.isDeepStrictEqual tests

These tests are a copy of the assert tests that verify the
deep equal comparison algorithm. There is no need to duplicate the
tests as changing one would require to change the tests in two
places without knowing which ones to actually rely upon.

Signed-off-by: Ruben Bridgewater <ruben@bridgewater.de>
PR-URL: #46593
Reviewed-By: Yagiz Nizipli <yagiz@nizipli.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>