PmCheck: Adjust recursion depth for inhabitation test
In #17977 (closed), we ran into the reduction depth limit of the typechecker.
That was only a symptom of a much broader issue: The recursion depth
of the coverage checker for trying to instantiate strict fields in the
nonVoid
test was far too high (100, the defaultMaxTcBound
).
As a result, we were performing quite poorly on T17977
.
Short of a proper termination analysis to prove emptyness of a type,
we just arbitrarily default to a much lower recursion limit of 3.
Fixes #17977 (closed).