This removes a bunch of weird code around the counter overflow check in
concatKDF and makes it actually work for different hash output sizes.

The overflow check worked as follows: concatKDF applies the hash function N
times, where N is roundup(kdLen, hashsize) / hashsize. N should not
overflow 32 bits because that would lead to a repetition in the KDF output.

A couple issues with the overflow check:

- It used the hash.BlockSize, which is wrong because the
  block size is about the input of the hash function. Luckily, all standard
  hash functions have a block size that's greater than the output size, so
  concatKDF didn't crash, it just generated too much key material.
- The check used big.Int to compare against 2^32-1.
- The calculation could still overflow before reaching the check.

The new code in concatKDF doesn't check for overflow. Instead, there is a
new check on ECIESParams which ensures that params.KeyLen is < 512. This
removes any possibility of overflow.

There are a couple of miscellaneous improvements bundled in with this
change:

- The key buffer is pre-allocated instead of appending the hash output
  to an initially empty slice.
- The code that uses concatKDF to derive keys is now shared between Encrypt
  and Decrypt.
- There was a redundant invocation of IsOnCurve in Decrypt. This is now removed
  because elliptic.Unmarshal already checks whether the input is a valid curve
  point since Go 1.5.

Co-authored-by: Felix Lange <fjl@twurst.com>

- Dump stats also for --bench flag.
- From memory stats only show number and size of allocations. This is what `test -bench` shows. I doubt others like number of GC runs are any useful, but can be added if requested.
- Now the mem stats are for single execution in case of --bench.

* add istanbul and muirGlacier to genesis states in README

* remove muirGlacier, relocate istanbul

* les: move execqueue into utilities package

execqueue is a util for executing queued functions
in a serial order which is used by both les server
and les client. Move it to common package.

* les: move randselect to utilities package

weighted_random_selector is a helpful tool for randomly select
items maintained in a set but based on the item weight.

It's used anywhere is LES package, mainly by les client but will
be used in les server with very high chance. So move it into a
common package as the second step for les separation.

* les: rename to utils

The test failed due to what appears to be fluctuations in time.Sleep, which is
not the actual method under test. This change modifies it so we compare the
metered Max to the actual time instead of the desired time.

This new API allows reading accounts and their content by address range.

Co-authored-by: Martin Holst Swende <martin@swende.se>
Co-authored-by: Felix Lange <fjl@twurst.com>

* cmd/clef: add newaccount command

* cmd/clef: document clef_New, update API versioning

* Update cmd/clef/intapi_changelog.md

Co-Authored-By: ligi <ligi@ligi.de>

* Update signer/core/uiapi.go

Co-Authored-By: ligi <ligi@ligi.de>

Co-authored-by: ligi <ligi@ligi.de>

* cmd, consensus: add option to disable mmap for DAG caches/datasets

* consensus: add benchmarks for mmap with/with lock

* core/state/snapshot: basic trie-to-hash implementation

* tests: validate snapshot after test

* core/state/snapshot: fix review concerns

core: bump txpool tx max size to 128KB

* eth: improve shutdown synchronization

Most goroutines started by eth.Ethereum didn't have any shutdown sync at
all, which lead to weird error messages when quitting the client.

This change improves the clean shutdown path by stopping all internal
components in dependency order and waiting for them to actually be
stopped before shutdown is considered done. In particular, we now stop
everything related to peers before stopping 'resident' parts such as
core.BlockChain.

* eth: rewrite sync controller

* eth: remove sync start debug message

* eth: notify chainSyncer about new peers after handshake

* eth: move downloader.Cancel call into chainSyncer

* eth: make post-sync block broadcast synchronous

* eth: add comments

* core: change blockchain stop message

* eth: change closeBloomHandler channel type

Turns out the way RDATA limits work is documented after all,
I just didn't search right. The trick to make it work is to
count UPSERTs twice.

This also adds an additional check to ensure TTL changes are
applied on existing records.

* cmd/devp2p: tweak DNS TTLs

* cmd/devp2p: bump treeNodeTTL to four weeks

metrics: disable CPU stats (gosigar) on iOS

Prior to this change, eth_call changed the balance of the sender account in the
EVM environment to 2^256 wei to cover the gas cost of the call execution.
We've had this behavior for a long time even though it's super confusing.

This commit sets the default call gasprice to zero instead of updating the balance,
which is better because it makes eth_call semantics less surprising. Removing
the built-in balance assignment also makes balance overrides work as expected.