Support mixed input/output in cutpoint handling of inout #5383
Description
From #5268:
This does handle the use case of inout as stand-in for unknown port direction, but while reviewing it I thought of another case of inout for which handling each bit of a port bus individually would be better: sometimes you see patterns where an inout port is used to assign a concatenation of fields, some of which are inputs and some are outputs.
The code in this PR is still an improvement for that case as well: Since it skips the port and doesn't create any conflicts, the subsequent setundef -undriven -anyseq in SBY should take care of that and the end result should still be correct, just with perhaps a spurious undriven signal warning. So let's merge this now and create a new issue for the other case that we can address later.
Originally posted by @nakengelhardt in #5268 (review)