Fix write_total_difficulty implementation signature and add a test for it

[peroket]

No description provided.

[codecov]

Codecov Report

Merging #643 (844a475) into master (a992e85) will increase coverage by 0.01%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #643      +/-   ##
==========================================
+ Coverage   82.52%   82.54%   +0.01%     
==========================================
  Files         176      176              
  Lines       15237    15237              
==========================================
+ Hits        12574    12577       +3     
+ Misses       2663     2660       -3     

Impacted Files	Coverage Δ
node/silkworm/db/access_layer.cpp	83.69% <100.00%> (+0.85%)	⬆️
core/silkworm/execution/evm.cpp	95.27% <0.00%> (-0.83%)	⬇️
core/silkworm/state/intra_block_state.cpp	97.46% <0.00%> (+0.94%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update a992e85...844a475. Read the comment docs.