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