The disaggregated storage multiversion "last-patch" passthrough suites (disagg_repl_jscore_passthrough_multiversion_last_patch_new_old / _old_new, generated by the disagg_repl_jscore_passthrough_multiversion_last_patch_gen Evergreen task) configure their fixture with old_bin_version: last_patch (see the disagg_multiversion.yml matrix suite override). This makes them always download the latest available 9.0.0-rcXXXX binary as the "old" binary.

After branching out 9.0, master now targets 9.1 (see SERVER-129707), so there is no 9.1.0-rcXXXX last-patch release available yet, and these suites fail to find a binary to download. As a temporary workaround, these suites were disabled from running on master.

The goal of this ticket is to make the suites automatically detect when no matching last-patch release binary is available for the current target version and skip themselves gracefully instead of failing, so they don't need to be manually disabled after every branch cut. Once implemented, re-enable the suites' execution on master.

A related complication to account for: DSC/disagg Mongod binaries are not necessarily built for every patch release. If the last release with a disagg binary is, for example, 9.1.19, and subsequent 9.1.2X patches or even a 9.2.0 minor/major release don't (yet) have a disagg binary published, the suites should keep testing against the latest disagg-compatible release (9.1.19 in this example) rather than either failing outright or silently skipping just because the newest overall release lacks a disagg binary. In other words, "last patch" for these suites needs to mean "latest release with a published disagg binary," which may lag behind the latest release with a published binary in general — potentially across a minor or major version boundary.