tests: Fix metadata.db download regression
tests: Fix metadata.db download regression

Commit 147cf6e62 moved the metadata.db from a Makefile dependency to an
unconditional command in the `shared` target. As the latter is phony,
this leads to unnecessarily downloading the metadata for every test run.
Revert that bit.

weldr/welder-web,jkozol/welder-web,weldr/welder-web,jkozol/welder-web,weldr/welder-web,jkozol/welder-web,jkozol/welder-web,weldr/welder-web