openmp, fortran: Revert to using tree expressions when translating Fortran OpenMP...

openmp, fortran: Revert to using tree expressions when translating Fortran OpenMP array sections

In the patch 'OpenACC 2.7: Implement reductions for arrays and records',
temporaries are used to hold the decl and bias of clauses resulting from array
sections, which breaks some assumptions made for map iterator support.

This patch reverts the change for OpenMP only.

gcc/fortran/

	* trans-openmp.cc (gfc_trans_omp_array_section): Use temporaries only
	when translating OpenACC.

gcc/testsuite/

	* gfortran.dg/gomp/target-enter-exit-data.f90: Revert expected tree
	dumps.