Defined input/output procedures are specified in 12.6.4.8. There are different
versions for read versus write and formatted versus unformatted, but they all
share the same basic set of dummy arguments.
I added several checking functions to check-declarations.cpp along with a test.
In the process of implementing this, I noticed and fixed a typo in
.../lib/Evaluate/characteristics.cpp.
Consider having one call to CheckDefinedIoProc() and using two std::visit() calls to calculate its last two arguments.