[CHIA-1562] validate block signature as part of run_block_generator()

[arvidn]

There is an opt-out for tests and maybe we'll need it in production too.

There are 3 main intentions:

1. Allow releasing the GIL for longer periods at a time, by combining executing CLVM, parsing conditions and validating the signature
2. Make the logic around validating signatures simpler, by always validating them when running a block (there's an opt-out for tests right now, and we may need it while transitioning).
3. (in the future) avoid copying all the public keys and messages back into python.

In this first version, the BLSCache is not thread safe. This would likely be a problem since we use run_block_generator() from threads in python. It should probably contain a Mutex to serialize access to it.

The new flag DONT_VALIDATE_SIGNATURE can be passed in to skip the validation.
The new field validated_signature on SpendBundleConditions can be used to ensure it was in fact validated.

The main changes are in conditions.rs. The pkm_pairs are collected, as they are parsed, into a single list in the ParseState object. Here: https://github.com/Chia-Network/chia_rs/compare/run_block_validate_signature?expand=1#diff-c93029cf40a6e979ca6c9b02528cfc71cad2e7099818a2deeb92cb9cf5cf344bR788

At the end, these key-message pairs are validated against the signature in this new function validate_signature(): https://github.com/Chia-Network/chia_rs/compare/run_block_validate_signature?expand=1#diff-c93029cf40a6e979ca6c9b02528cfc71cad2e7099818a2deeb92cb9cf5cf344bR1502

[coveralls-official]

Pull Request Test Coverage Report for Build 11259684754

Details

• 284 of 285 (99.65%) changed or added relevant lines in 8 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.3%) to 83.638%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
crates/chia-consensus/src/gen/conditions.rs	207	208	99.52%

Totals
Change from base Build 11238444984:	0.3%
Covered Lines:	12708
Relevant Lines:	15194

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💛 - Coveralls

[arvidn]

note that the meat of this patch is in conditions.rs, which github collapses by default in the diff view. Almost everything else are changes to tests to compensate.