Polishing Swarm<T>

[longfin]

This PR addresses two bugs in Swarm<T> as below

1. a bug that Swarm<T> had not received block headers after failing to receive previous blocks.
2. a bug that Swarm<T> had thrown InvalidGenesisBlockException when reorg chain repeatedly.

[codecov]

Codecov Report

Merging #996 into main will increase coverage by 0.36%.
The diff coverage is 90.19%.

@@            Coverage Diff             @@
##             main     #996      +/-   ##
==========================================
+ Coverage   88.81%   89.17%   +0.36%     
==========================================
  Files         288      324      +36     
  Lines       26766    29301    +2535     
==========================================
+ Hits        23771    26130    +2359     
- Misses       1466     1608     +142     
- Partials     1529     1563      +34     

Impacted Files	Coverage Δ
...ests/Blockchain/Renderers/AnonymousRendererTest.cs	83.87% <ø> (-3.72%)	⬇️
...t.Tests/Blockchain/Renderers/LoggedRendererTest.cs	99.11% <ø> (-0.14%)	⬇️
Libplanet.Tests/Common/Action/ExecuteRecord.cs	60.00% <0.00%> (-40.00%)	⬇️
Libplanet.Tests/Common/DumbRenderer.cs	93.33% <ø> (ø)
Libplanet.Tests/Net/SwarmTest.Fixtures.cs	100.00% <ø> (ø)
...lanet.Tests/Net/SwarmTest.TrustedStateCompleter.cs	98.63% <ø> (ø)
Libplanet.Tests/Store/StateStoreTracker.cs	60.00% <0.00%> (ø)
Libplanet/Action/PolymorphicAction.cs	100.00% <ø> (ø)
...ibplanet/Blockchain/Renderers/AnonymousRenderer.cs	100.00% <ø> (ø)
Libplanet/Blocks/Block.cs	85.42% <ø> (-0.20%)	⬇️
... and 106 more