Apply term substitution to crucible_{pre,post}cond arguments in overrides.
Apply term substitution to crucible_{pre,post}cond arguments in overrides.

This fixes a bug where proof obligations would be generated that mention
variables from the original spec that aren't even in scope for the outer
function.

GaloisInc/saw-script,GaloisInc/saw-script,GaloisInc/saw-script,GaloisInc/saw-script,GaloisInc/saw-script