EIP-2537 BLS12 381 Precompiles

Documentation for tests/prague/eip2537_bls_12_381_precompiles@7b8124a7.

Generate fixtures for these test cases for Bpo2 with:

fill -v tests/prague/eip2537_bls_12_381_precompiles --fork Bpo2

Tests EIP-2537: Precompile for BLS12-381 curve operations.