openmp: Fix up !$omp target parallel handling

The PR93329 fix revealed we ICE on !$omp target parallel, this change fixes
that.

2020-01-22  Jakub Jelinek  <jakub@redhat.com>

	* parse.c (parse_omp_structured_block): Handle ST_OMP_TARGET_PARALLEL.
	* trans-openmp.c (gfc_trans_omp_target)
	<case EXEC_OMP_TARGET_PARALLEL>: Call pushlevel first.

	* gfortran.dg/gomp/target-parallel1.f90: New test.
	* gfortran.dg/goacc/pr93329.f90: Enable commented out target parallel
	test.
6 files changed