fortran: Fix up gfc_trans_oacc_construct [PR104717]

fortran: Fix up gfc_trans_oacc_construct [PR104717]

So that move_sese_region_to_fn works properly, OpenMP/OpenACC constructs
for which that function is invoked need an extra artificial BIND_EXPR
around their body so that we move all variables of the bodies.

The C/C++ FEs do that both for OpenMP constructs like OMP_PARALLEL, OMP_TASK
or OMP_TARGET and for OpenACC constructs that behave similarly to
OMP_TARGET, but the Fortran FE only does that for OpenMP constructs.

The following patch does that for OpenACC constructs too.

	PR fortran/104717
	gcc/fortran/
	* trans-openmp.cc (gfc_trans_oacc_construct): Wrap construct body
	in an extra BIND_EXPR.
	gcc/testsuite/
	* gfortran.dg/goacc/pr104717.f90: New test.
	* gfortran.dg/goacc/privatization-1-compute-loop.f90: Adjust.
	libgomp/
	* testsuite/libgomp.oacc-fortran/privatized-ref-2.f90: Adjust.

Co-authored-by: Thomas Schwinge <thomas@codesourcery.com>