go.mod: update golang.org/x/crypto to fix a Go 1.14 race rejection

eth: fix transaction announce/broadcast goroutine leak

This is supposed to fix the occasional failures in 
TestCancel* on Travis CI.

Includes difficulty tests for EIP2384 aka MuirGlacier.

typo in func name in the comment

This was missing because I forgot to wrap it when bind.CallOpts.From
as added.

* les: separate peer into clientPeer and serverPeer

* les: address comments

This makes eth_call and eth_estimateGas use the zero address
as sender when the "from" parameter is not supplied.
Co-authored-by: Felix Lange <fjl@twurst.com>

eth/fetcher: remove randomness from test data

The new goja version supports the 'escape' and 'unescape' built-in functions.
This fixes #20693

params: update CHTs for the v1.9.11 release

This removes the error added in #20597 in favor of a log message at
error level. Failing to start broke a bunch of people's setups and is
probably not the right thing to do for this check.

This fixes a bunch of cases where a timeout in the test would leak
a goroutine.

This adds additional logic to re-resolve the root name of a tree when a
couple of leaf requests have failed. We need this change to avoid
getting into a failure state where leaf requests keep failing for half
an hour when the tree has been updated.

eth: don't enforce minimum broadcast, fix broadcast test

This event was added for the dashboard, but we don't need it anymore
since the dashboard is gone.

travis, appveyor, build: bump builder Go to 1.13.8

* cmd/faucet: add Rlock to protect f.reqs in apiHandler

* cmd/faucet: make a locked copy of f.reqs

* node: expose config in service context

* eth: integrate p2p/dnsdisc

* cmd/geth: add some DNS flags

* eth: remove DNS URLs

* cmd/utils: configure DNS names for testnets

* params: update DNS URLs

* cmd/geth: configure mainnet DNS

* cmd/utils: rename DNS flag and fix flag processing

* cmd/utils: remove debug print

* node: fix test