When SignedData is parsed from a Buffer, .verify() fails to select the right signer certificate in the 3.0.15 release build

[sander]

Example: https://github.com/sander/pkijs-buffer-bug

Hypothesis: when searching through SignedData.certificates, any IssuerAndSerialNumber.serialNumber from the same Buffer matches, since the Integer.isEqual check compares the whole buffer content instead of just the slices. I faced similar issues in: PeculiarVentures/pvtsutils#13.

I could not reproduce this from within the PKI.js repository or with a local npm build artifact from 80afe52. So possibly the bug is caused by the particular build process that was used to release 3.0.15.