feat: allow taking benchmarking instance in NewAssert

[ivokub]

Description

Sometimes when trying to benchmark some existing tests (i.e. compile time, proving time etc), I'd want to copy-paste current test and then run it. But as test.Assert does not support taking *testing.B as input then I had to rewrite a lot.

This PR makes it take either and then switch the implementation. Benchmarking with Assert.CheckCircuit doesn't make much sense as it reuses compiled circuits, but I added a comment to indicate that. And we usually benchmark only a very specific part.

Type of change

• New feature (non-breaking change which adds functionality)

Checklist:

• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• I did not modify files generated from templates
• golangci-lint does not output errors locally
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules