ftn: an IF statement guarding STOP in device code: the STOP runs although its condition is false (target loop), or an internal compiler error (directly in a target region)

! # Draft finding: omp52-w-stop-unreached on cce19
!
! - compiler: cce19
! - toolchain: cce19; arch: gfx942; machine: tuolumne; memory mode: unified; opt: -O2
! - program: catalog omp52-w-stop-unreached (f90, version 52, sha256 4ae6862a92abf979)
! - expected: check=pass (trusted; elision + model)
! - actual: crash Thread execution stopped at FILE ../../omp52-w-stop-unreached.f90 LINE 28 due to a regular STOP statement. ...
!   (repeated; crash: SIGABRT; without mandatory: crash: SIGABRT)
! - verdict: compiler_bug by rule R20-runtime-bug: a legal program fails at run time, deterministically, against an expected value
!   from two or more independent sources with an executed witness, and another toolchain, mode, arch or the elision gives the
!   expected value
! - reason: expected trusted check=pass (elision + model): stored main verdict: elision + model agree; witnesses: afar/gfx942/copy,
!   afar/gfx942/copy (port:omp52-c-w-stop-unreached), afar/gfx942/unified, afar/gfx942/unified (port:omp52-c-w-stop-unreache ...
! - citations: RUL-DERIVED-NEEDS-EXECUTION (rulings.md); RUL-WITNESS-PER-MODE (rulings.md);
!   RUL-SAME-COMPILER-RUNS (rulings.md); RUL-PRESENCE-WITNESS (rulings.md); RUL-METAMORPHIC-OTHER-FAMILY
!   (rulings.md)
! - legality: legal: offload.engine.prerun.check accepts it (rerun: offload.engine.rules with the
!   race rule and the restriction checks, and the AFAR flang front end, not under test here); no
!   compiler under test, gfortran or gcc is a legality witness
! - witnesses: afar/gfx942/copy, afar/gfx942/copy (port:omp52-c-w-stop-unreached), afar/gfx942/unified, afar/gfx942/unified
!   (port:omp52-c-w-stop-unreached), cce19/gfx942/copy (port:omp52-c-w-stop-unreached), cce19/gfx942/unified
!   (port:omp52-c-w-stop-unrea ...
! - withdrawn: none
!
! Generated by compliance.widen (OpenMP 5.2, free-form Fortran; catalog widening). Do not edit.
! id: omp52-w-stop-unreached
! primary atom: base.device.stop
! atoms: base.device.stop
! legal: yes
! observable: yes
! ran_on_host: inside the target region of interest
! evidence: construct
! needs: none
! std: f2008
! feature: a STOP statement in device code that is not executed
! spec: OpenMP 5.2 §4.3, p.76: a structured block may contain STOP or ERROR STOP statements
program wide_prog
  use omp_lib, only: omp_is_initial_device
  implicit none
  integer, parameter :: n = 64
  integer :: a(n), b(n), ref(n)
  integer :: i, host_flag
  logical :: ok
  do i = 1, n
    a(i) = i
    b(i) = 0
    ref(i) = 2*i + 1
  end do
  host_flag = 1
  !$omp target teams distribute parallel do map(to: a) map(from: b) map(tofrom: host_flag)
  do i = 1, n
    if (a(i) < 0) stop 1
    b(i) = 2*a(i) + 1
    if (i == 1) host_flag = merge(1, 0, omp_is_initial_device())
  end do
  !$omp end target teams distribute parallel do
  ok = all(b == ref)
  print '(a,i0,a,a)', 'RESULT ran_on_host=', host_flag, ' check=', merge('pass', 'fail', ok)
end program wide_prog