* all: move main transaction pool into a subpool * go.mod: remove superfluous updates * core/txpool: review fixes, handle txs rejected by all subpools * core/txpool: typos
* tests/fuzzers, common/bitutil: make fuzzers use correct returnvalues + remove output * tests/fuzzers/stacktrie: fix duplicate-key insertion in stacktrie (false positive) * tests/fuzzers/stacktrie: fix compilation error * tests/fuzzers: linter nits