test: remove common.expectsInternalAssertion

Remove convenience function for internal assertions. It is only used
once.

Signed-off-by: Rich Trott <rtrott@gmail.com>

PR-URL: https://github.com/nodejs/node/pull/32057


Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Anto Aravinth <anto.aravinth.cse@gmail.com>