[CHIA-2710] Add new stress test with multiple spends

[matt-o-how]

Adds a new stress test which spends 25,000 coins each making 50 pairs of messages (to use the free 100 conditions) - the generator creates these spends dynamically and does not re-use the list of messages

[coveralls-official]

Pull Request Test Coverage Report for Build 16905792995

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.

• For more information on this, see Tracking coverage changes with pull request builds.
• To avoid this issue with future PRs, see these Recommended CI Configurations.
• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 1 unchanged line in 1 file lost coverage.
• Overall coverage increased (+17.3%) to 83.56%

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Files with Coverage Reduction	New Missed Lines	%
wheel/src/api.rs	1	85.57%

Totals
Change from base Build 16762008470:	17.3%
Covered Lines:	14755
Relevant Lines:	17658

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💛 - Coveralls