Add new stress tests for the generator based on the new costing

[matt-o-how]

Given the new costing for conditions that is coming in we want to stress test the generators in the expensive cases that were not available before. Namely large numbers of Message conditions.

[coveralls-official[bot]]

Pull Request Test Coverage Report for Build 15347830638

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

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Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 28 unchanged lines in 1 file lost coverage.
• Overall coverage decreased (-0.02%) to 65.225%

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Files with Coverage Reduction	New Missed Lines	%
crates/chia-protocol/src/proof_of_space.rs	28	11.67%
<!--	Total:	28

Totals
Change from base Build 15277433467:	-0.02%
Covered Lines:	11072
Relevant Lines:	16975

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💛 - Coveralls

[arvidn]

you probably don't need so many different variants of the messages stress test. the highest number that still passes (run_block_generator2()) is probably enough. I believe that would be the most expensive one