core, txpool: less allocations when handling transactions (#21232)

* core: use uint64 for total tx costs instead of big.Int

* core: added local tx pool test case

* core, crypto: various allocation savings regarding tx handling

* Update core/tx_list.go

* core: added tx.GasPriceIntCmp for comparison without allocation

adds a method to remove unneeded allocation in comparison to tx.gasPrice

* core: handle pools full of locals better

* core/tests: benchmark for tx_list

* core/txlist, txpool: save a reheap operation, avoid some bigint allocs

Co-authored-by: Martin Holst Swende <martin@swende.se>
# Conflicts:
#	common/math/integer.go
#	core/tx_list.go
#	core/tx_pool.go
#	core/types/transaction.go