fix: remove dead code - secp256k1 affine point mul

[pdobacz]

This PR is more of a question - is it OK to move this code into the unittest convenience wrapper? It is not used in any code covered by precompile tests.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 84.83%. Comparing base (40a3d29) to head (812b6db).
⚠️ Report is 1 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #1346   +/-   ##
=======================================
  Coverage   84.83%   84.83%           
=======================================
  Files         169      169           
  Lines       20356    20356           
  Branches     4121     4121           
=======================================
  Hits        17268    17268           
  Misses        438      438           
  Partials     2650     2650           

Flag	Coverage Δ
eest-develop	79.83% <ø> (+0.02%)	⬆️
eest-develop-gmp	14.67% <0.00%> (ø)
eest-legacy	10.11% <0.00%> (ø)
eest-legacy-silkpre	16.21% <0.00%> (ø)
evmone-unittests	81.24% <100.00%> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Components	Coverage Δ
core	92.71% <ø> (-0.01%)	⬇️
tooling	84.69% <ø> (ø)
tests	81.42% <100.00%> (+<0.01%)	⬆️

Files with missing lines	Coverage Δ
lib/evmone_precompiles/secp256k1.cpp	100.00% <ø> (ø)
test/unittests/evmmax_secp256k1_test.cpp	76.79% <100.00%> (+0.25%)	⬆️

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[chfast]

Yes, good idea.