This helps libFuzzer:
FUZZ=http_request ./bld/bin/fuzz -dict=./fuzz_dicts/http_request.dict ./fuzz_corpora/http_request/
(crashes in a few seconds)
Without the dict, it takes a longer time (or maybe doesn't crash at all). See https://github.com/bitcoin/bitcoin/pull/35759#issuecomment-5048038142