fast sync and short chain

[ucwong]

No description provided.

[codecov]

Codecov Report

Merging #744 into master will decrease coverage by 0.01%.
The diff coverage is 22.22%.

@@            Coverage Diff             @@
##           master     #744      +/-   ##
==========================================
- Coverage   50.36%   50.34%   -0.02%     
==========================================
  Files         408      408              
  Lines       52737    52743       +6     
==========================================
- Hits        26559    26555       -4     
- Misses      24175    24190      +15     
+ Partials     2003     1998       -5     

Impacted Files	Coverage Δ
core/blockchain.go	23.63% <0.00%> (-0.08%)	⬇️
ctxc/downloader/downloader.go	78.27% <100.00%> (-0.39%)	⬇️
p2p/rlpx.go	69.40% <0.00%> (-1.99%)	⬇️
p2p/simulations/mocker.go	33.63% <0.00%> (-1.82%)	⬇️
core/tx_pool.go	76.98% <0.00%> (-0.80%)	⬇️
rpc/client.go	83.10% <0.00%> (-0.69%)	⬇️
p2p/simulations/http.go	69.56% <0.00%> (-0.55%)	⬇️
p2p/server.go	66.98% <0.00%> (ø)
ctxc/downloader/queue.go	81.26% <0.00%> (+0.46%)	⬆️
... and 4 more