This commit adds all changes needed for the merge of swarm-network-rewrite.
The changes:

- build: increase linter timeout
- contracts/ens: export ensNode
- log: add Output method and enable fractional seconds in format
- metrics: relax test timeout
- p2p: reduced some log levels, updates to simulation packages
- rpc: increased maxClientSubscriptionBuffer to 20000

 #15685 made peer_test.go more portable by using random free port instead of hardcoded port 30303 (#15687)

Improves test portability by resolving 127.0.0.1:0
to get a random free port instead of the hard coded one. Now
the test works if you have a running node on the same
interface already.

Fixes #15685

console/console: correct some comments typo

core/asm/lexer: correct comments typo

This PR fixes a retriever logic bug. When a peer had a soft timeout
and then a response arrived, it always assumed it was the same peer
even though it could have been a later requested one that did not time
out at all yet. In this case the logic went to an illegal state and
deadlocked, causing a goroutine leak.

Fixes #16243 and replaces #16359.
Thanks to @riceke for finding the bug in the logic.

ToECDSAPub was unsafe because it returned a non-nil key with nil X, Y in
case of invalid input. This change replaces ToECDSAPub with
UnmarshalPubkey across the codebase.

internal/ethapi: reduce pendingTransactions to O(txs+accs) from O(txs*accs)

metrics: fix gofmt linter warnings

* ethdb: gratefullly handle quit channel

* ethdb: minor polish

* core/rawdb: use wrappered helper to assemble key

* core/rawdb: wrappered helper to assemble key

* core/rawdb: rewrite the wrapper, pass common.Hash

trie: don't report the root flushlist as an alloc

rpc: support returning nil pointer big.Ints (null)

* core: improve getBadBlocks to return full block rlp

* core, eth, ethapi: changes to getBadBlocks formatting

* ethapi: address review concerns

The error produced when using a Parity RPC was the following:

ERROR: transaction did not get mined: failed to get tx for txid 0xbdeb094b3278019383c8da148ff1cb5b5dbd61bf8731bc2310ac1b8ed0235226: json: cannot unmarshal non-string into Go struct field txExtraInfo.blockHash of type common.Hash

This change introduces 

    ethkey changepassphrase <keyfile>

to change the passphrase of a key file.

optimization code

core: concurrent background transaction sender ecrecover

* trie: reduce hasher allocations

name    old time/op    new time/op    delta
Hash-8    4.05µs ±12%    3.56µs ± 9%  -12.13%  (p=0.000 n=20+19)

name    old alloc/op   new alloc/op   delta
Hash-8    1.30kB ± 0%    0.66kB ± 0%  -49.15%  (p=0.000 n=20+20)

name    old allocs/op  new allocs/op  delta
Hash-8      11.0 ± 0%       8.0 ± 0%  -27.27%  (p=0.000 n=20+20)

* trie: bump initial buffer cap in hasher

* vendor: added vendor packages necessary for the swarm-network-rewrite merge into ethereum master

* vendor: removed multihash deps

params: fix golint warnings

Allow the --abi flag to be given - to indicate that it should read the
ABI information from standard input. It expects to read the solc output
with the --combined-json flag providing bin, abi, userdoc, devdoc, and
metadata, and works very similarly to the internal invocation of solc,
except it allows external invocation of solc.

This facilitates integration with more complex solc invocations, such
as invocations that require path remapping or --allow-paths tweaks.

Simple usage example:

    solc --combined-json bin,abi,userdoc,devdoc,metadata *.sol | abigen --abi -