This patch refactors include-module.f90:
- rename the test file as use-module.f90 to better highlight which driver feature is being tested
- move tests for diagnostics to use-module-error.f90 (it tests that -J/-module-dir can only be used once)
- make sure that f18 is tested when FLANG_BUILD_NEW_DRIVER is set to Off
- add tests for when all module files are successfully discovered and loaded
With this patch, there should be a clear separation into 3 scenarios in
use-module.f90:
- Everything is OK
- One module file wasn't found (missing include path for basictestingmoduletwo.mod)
- Two module files are found, but the test requires basictestingmoduleone.mod from both Inputs and Inputs/module-dir. Only the latter is found.
Depends on: D97164
Rather than check in the .mod files (whose format can change at any time) it would be better to check in the Fortran source and compile it for tests that need it. It would make the tests less fragile.