test: fix invalid modulesLength for DSA keygen

During key generation, the default dsa_builtin_paramgen will reset
modulusLength to 512. But in dsa_builtin_paramgen2 this does not
happen, leading to lockup in FIPS mode.

PR-URL: https://github.com/nodejs/node/pull/23732
Refs: https://github.com/nodejs/node/pull/23430


Reviewed-By: Sam Roberts <vieuxtech@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>