Add a way for running the tests with different epoch/clarity versions

[Acaccia]

Issue #340 showed a bug that happened at epoch20 but not at the latest one.

It seems that the typechecker phase runs two different versions of the typechecker depending if epoch >= 2.1, as we can see in the run_analysis function.

We should add new steps to our current tests to make sure that it works with both versions of the typechecker.

We should also investigate if the clarity version can provoke bugs too.

[smcclellan]

Closed by #498.

[Acaccia]

This PR doesn't add tests for different epochs with same Clarity version.

[csgui]

@Acaccia I think it’s not necessary to test earlier epochs, since clarity-wasm will not be active until later epochs (currently set to 3.0). It is important to test the different Clarity versions, that is what we are already doing. Don’t you think?

[Acaccia]

From what I understood, the compiler is supposed to work for already deployed contracts.