test: fix flaky key pair generation test
There is a very small chance (about 0.4%) that OpenSSL will successfully decrypt a key without the correct passphrase and will then fail while parsing its ASN.1 structure. In those rare cases, the error message will be different.
Fixes: https://github.com/nodejs/node/issues/22978
Checklist
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make -j4 test
(UNIX), orvcbuild test
(Windows) passes -
tests and/or benchmarks are included -
commit message follows commit guidelines