Ninja: Fix Fortran INCLUDE directive dependencies when not preprocessing

Since commit b0a6161190 (Fortran: Add Fortran_PREPROCESS property,
2020-04-24, v3.18.0-rc1~116^2~3), if `Fortran_PREPROCESS` is `OFF`, the
Ninja generator does not properly detect dependencies on sources loaded
via the Fortran INCLUDE directive.  Fix this and add a test.