openmp: Teach omp_code_to_statement about rest of OpenMP statements

openmp: Teach omp_code_to_statement about rest of OpenMP statements

The omp_code_to_statement function added with the initial OpenACC support
only handled small subset of the OpenMP statements, leading to ICE if
any other OpenMP directive appeared inside of OpenACC directive.

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

	PR fortran/93329
	* openmp.c (omp_code_to_statement): Handle remaining EXEC_OMP_*
	cases.

	* gfortran.dg/goacc/pr93329.f90: New test.