precompiles: Fallback to single mul in BLS MSM

[chfast]

If the number of valid and non-zero inputs to BLS MSM is 1 use simpler single point multiplication.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 94.21%. Comparing base (8e4a055) to head (01e0cfb).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #1046 +/- ## ======================================= Coverage 94.21% 94.21% ======================================= Files 153 153 Lines 15934 15940 +6 ======================================= + Hits 15012 15018 +6 Misses 922 922 ``` | [Flag](https://app.codecov.io/gh/ethereum/evmone/pull/1046/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=ethereum) | Coverage Δ | | |---|---|---| | [eof_execution_spec_tests](https://app.codecov.io/gh/ethereum/evmone/pull/1046/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=ethereum) | `17.53% <0.00%> (-0.01%)` | :arrow_down: | | [ethereum_tests](https://app.codecov.io/gh/ethereum/evmone/pull/1046/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=ethereum) | `27.33% <0.00%> (-0.02%)` | :arrow_down: | | [ethereum_tests_silkpre](https://app.codecov.io/gh/ethereum/evmone/pull/1046/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=ethereum) | `19.14% <0.00%> (-0.02%)` | :arrow_down: | | [execution_spec_tests](https://app.codecov.io/gh/ethereum/evmone/pull/1046/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=ethereum) | `20.48% <100.00%> (+0.03%)` | :arrow_up: | | [unittests](https://app.codecov.io/gh/ethereum/evmone/pull/1046/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=ethereum) | `89.01% <100.00%> (+<0.01%)` | :arrow_up: | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=ethereum#carryforward-flags-in-the-pull-request-comment) to find out more. | [Files with missing lines](https://app.codecov.io/gh/ethereum/evmone/pull/1046?dropdown=coverage&src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=ethereum) | Coverage Δ | | |---|---|---| | [lib/evmone\_precompiles/bls.cpp](https://app.codecov.io/gh/ethereum/evmone/pull/1046?src=pr&el=tree&filepath=lib%2Fevmone_precompiles%2Fbls.cpp&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=ethereum#diff-bGliL2V2bW9uZV9wcmVjb21waWxlcy9ibHMuY3Bw) | `100.00% <100.00%> (ø)` | |