Remove Fortran PROHIBIT checks now handled by Python validator

The three build-flag compatibility checks moved to case_validator.py
in the previous commit no longer need Fortran-side enforcement.
Remove them and their now-empty subroutines:

- pre_process/m_checker.fpp: s_check_parallel_io (parallel_io + --no-mpi)
- simulation/m_checker.fpp: s_check_inputs_geometry_precision (3D cyl + --single)
- post_process/m_checker.fpp: s_check_inputs_output_format (precision=2 + --single)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: sbryngelson

src/post_process/m_checker.fpp

@@ -24,16 +24,8 @@ contains
     !> Checks compatibility of parameters in the input file.
         !! Used by the post_process stage
     impure subroutine s_check_inputs
-
-        call s_check_inputs_output_format
-
     end subroutine s_check_inputs
 
-    !> Checks constraints on output format parameters
-    impure subroutine s_check_inputs_output_format
-        @:PROHIBIT(precision == 2 .and. wp == sp)
-    end subroutine s_check_inputs_output_format
-
     !> Checks constraints on fft_wrt
     impure subroutine s_check_inputs_fft
         integer :: num_procs_y, num_procs_z

src/pre_process/m_checker.fpp

@@ -24,16 +24,6 @@ contains
     !> Checks compatibility of parameters in the input file.
         !! Used by the pre_process stage
     impure subroutine s_check_inputs
-
-        call s_check_parallel_io
-
     end subroutine s_check_inputs
 
-    !> Checks if mpi is enabled with parallel_io
-    impure subroutine s_check_parallel_io
-#ifndef MFC_MPI
-        @:PROHIBIT(parallel_io, "MFC built with --no-mpi requires parallel_io=F")
-#endif
-    end subroutine s_check_parallel_io
-
 end module m_checker

src/simulation/m_checker.fpp

@@ -36,7 +36,6 @@ contains
             else if (recon_type == MUSCL_TYPE) then
                 call s_check_inputs_muscl
             end if
-            call s_check_inputs_geometry_precision
         end if
 
         call s_check_inputs_time_stepping
@@ -76,14 +75,6 @@ contains
             "For 3D simulation, p must be greater than or equal to (num_stcls_min*muscl_order - 1), whose value is "//trim(numStr))
     end subroutine s_check_inputs_muscl
 
-    !> Checks constraints on geometry and precision
-    impure subroutine s_check_inputs_geometry_precision
-        ! Prevent spherical geometry in single precision
-#ifdef MFC_SINGLE_PRECISION
-        @:PROHIBIT(.not. (cyl_coord .neqv. .true. .or. (cyl_coord .and. p == 0)), "Fully 3D cylindrical grid (geometry = 3) is not supported in single precision.")
-#endif
-    end subroutine s_check_inputs_geometry_precision
-
     !> Checks constraints on time stepping parameters
     impure subroutine s_check_inputs_time_stepping
         if (.not. cfl_dt) then