How to use Chrome's CRL sets (or some master CRL list) as a CRL file?

This may not be possible, at least in the form that you'd like.

Consider that in Chrome's CRLsets, there are (possibly) multiple revoked certificates from multiple CAs. A single CRL file which contains certificate from multiple CAs is known as an "indirect CRL". Indirect CRLs are poorly supported; see here and here; OpenSSL may not be able to do this.

In addition, as @bentek mentions, it looks like the CRLsets format is not compatible. Specifically, the CRLsets format does not contain all of the necessary CRL fields; see RFC 5280, Section 5.1. CRLsets contains (per its documentation) the SHA-256 hash of the Subject Public Key Info for the issuing certs, and the certificate serial numbers for revoked certificates from that issuing cert. There is not enough information to reconstruct a direct CRL (i.e. one CRL file per CA), sadly, if we wanted to. The biggest lack/omission, IMHO, is the name (DN) of the issuer of the revoked cert. CRLsets gives us a "fingerprint" (the SHA-256 SPKI hash), but mapping that fingerprint to the DN of the cert in question, given the scope of the Internet, would not be an easy task.