* rpc: make subscription test faster
reduces time for TestClientSubscriptionChannelClose
from 25 sec to < 1 sec.
* trie: cache trie nodes for faster sanity check
This reduces the time spent on TestIncompleteSyncHash
from ~25s to ~16s.
* core/forkid: speed up validation test
This takes the validation test from > 5s to sub 1 sec
* core/state: improve snapshot test run
brings the time for TestSnapshotRandom from 13s down to 6s
* accounts/keystore: improve keyfile test
This removes some unnecessary waits and reduces the
runtime of TestUpdatedKeyfileContents from 5 to 3 seconds
* trie: remove resolver
* trie: only check ~5% of all trie nodes
146e8d999c