Currently it was not possible to run just the BlockToJsonVerboes benchmarsk because it did not set up everything it needed, running bench_bitcoin -filter=BlockToJsonVerbose caused this assert to fail:
bench_bitcoin: chainparams.cpp:506: const CChainParams& Params(): Assertion `globalChainParams' failed.
Initializing TestingSetup fixes this.
This is a backport of core#20998