CI: tests 7, 8, 9 and 14 fail on Windows with Flang: "End of file during input" in `pnm.F90`

[gha3mi]

On Windows with the Flang compiler, the following tests are failing in CI:

Failing tests:

• Test 7
• Test 8
• Test 9
• Test 14

Error messages:

fatal Fortran runtime error(D:\a\forimage\forimage\src\pnm.F90:752): End of file during input  
fatal Fortran runtime error(D:\a\forimage\forimage\src\pnm.F90:728): End of file during input  
fatal Fortran runtime error(D:\a\forimage\forimage\src\pnm.F90:740): End of file during input