Running SAT-based CEX minimization with multiple POs runs into an
assertion. This makes it produce an error message instead.

Invoking 'constr -r' converts constraints into POs but does not fully
remove them. Now 'constr -pr' can be used to completely remove them,
leaving the set of non-constraint POs unchanged.

provide a fallback for systems without RLIMIT_AS

Some platforms were already listed, this includes OpenBSD to the list
and makes it easier to add more.

This reverts commit fd2c9b1c.

Add support for WASI platform in Wln_ConvertToRtl

read_cex: Allow reading cex that has extra registers