feat: modexp precompile 384 bits

[tekkac]

Time spent on this PR:

Pull request type

Please check the type of change your PR introduces:

• Bugfix
• Feature
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no api changes)
• Build related changes
• Documentation content changes
• Other (please describe):

What is the current behavior?

Running 8 test(s) from src/
[PASS] evm::precompiles::modexp::tests::test_modexp_berlin_empty_input (gas: ~133)
[PASS] evm::precompiles::modexp::tests::test_modexp_eip198_example_1 (gas: ~635)
[PASS] evm::precompiles::modexp::tests::test_modexp_circuit (gas: ~544)
[PASS] evm::precompiles::modexp::tests::test_modexp_edge_case_circuit (gas: ~9)
[PASS] evm::precompiles::modexp::tests::test_modexp_eip198_example_2 (gas: ~312)
[PASS] evm::precompiles::modexp::tests::test_modexp_precompile_input_output_worst (gas: ~953)
[PASS] evm::precompiles::modexp::tests::test_modexp_circuit_worst_case (gas: ~953)
[PASS] evm::precompiles::modexp::tests::test_modexp_precompile_input_output_all_sizes (gas: ~22497)

Resolves #1496

What is the new behavior?

• modexp precompiled implemented with circuit up to 384 bits (48 bytes)
• passes basic tests and some EIP test vectors
• Custom input output needed because of non-standard integer types from circuits.

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This change is 

[enitrat]

great :)

[Eikix]

Why are ef-tests failing?

[tekkac]

Why are ef-tests failing?

passing now after updating branch

[enitrat]

thanks, will do a second pass soon

[enitrat]

perfect now 💯

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 63.5%. Comparing base (474951c) to head (4572dc5).
Report is 4 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##            main   #1513     +/-   ##
=======================================
- Coverage   63.6%   63.5%   -0.1%     
=======================================
  Files         44      44             
  Lines       8332    8332             
=======================================
- Hits        5301    5298      -3     
- Misses      3031    3034      +3     

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[ClementWalter]

can do a follow up PR, but in a second thought we said that we could move these tests to end to end to make direct call to the precompile, instead of unit with generated data.

[ClementWalter]

I'm fine with merging as is if it's all ✅ and do follow up PRs for

• possible improvements cc @feltroidprime
• refactoring tests to end-to-end directly cc @enitrat