Most derived contracts: Filter Test/Mock contracts

[montyly]

slither.contracts_derived can return Mock / Test contracts, instead of returning the expected derived contracts.

We need to filter Mock/Test and also return contracts that are only inherited by tests

slither/slither/core/slither_core.py

Lines 173 to 177 in c0c581b

	def contracts_derived(self) -> List[Contract]:
	"""list(Contract): List of contracts that are derived and not inherited."""
	inheritance = (x.inheritance for x in self.contracts)
	inheritance = [item for sublist in inheritance for item in sublist]
	return [c for c in self._contracts.values() if c not in inheritance and not c.is_top_level]

[0xalpharush]

I started work on this here https://github.com/crytic/slither/tree/contracts-derived-filter-tests. We need to address a couple things:

• filter out analyzing test directories with config(also clarify the difference between not analyzing and excluding results with --filter-paths)
• allow pattern matching besides "Test" and "Mock"

ref #759
xref crytic/crytic-compile#435