Merge #16267: bench: Benchmark blockToJSON

Summary:
91509ffe247b0eacbf84214c7c9c3f8a0012f2eb bench: Benchmark blockToJSON (Kirill Fomichev)

Pull request description:

Related:
- "getblock performance issue on verbosity" https://github.com/bitcoin/bitcoin/issues/15925
- "refactor: Avoid UniValue copy constructor" #15974

ACKs for top commit:

laanwj:
  ACK 91509ffe247b0eacbf84214c7c9c3f8a0012f2eb

Tree-SHA512: e70b12cb31921c7527bde334f52f39776da698b6bbdb196079a8b68478c67585a5bd7bed7403f65166bd604f7ed60778c53dc064d743bb8368318a1283d1073e

Backport of Core PR16267

Also cleans up the includes per Core PR16659

Depends on D5980

Test Plan:

ninja check
ninja src/bench/bitcoin-bench
./src/bench/bitcoin-bench -filter=BlockToJsonVerbose

Reviewers: #bitcoin_abc, deadalnix

Reviewed By: #bitcoin_abc, deadalnix

Differential Revision: https://reviews.bitcoinabc.org/D5981