autogen: use paste crate to gen test functions for each circuit,gas verifier

[pinkiebell]

Make full use of concurrency in autogen workflow

[coveralls]

Pull Request Test Coverage Report for Build 4323736441

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 89.679%

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Totals
Change from base Build 4322783649:	0.0%
Covered Lines:	782
Relevant Lines:	872

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💛 - Coveralls