[OpenACC] Extract 'pass_oacc_loop_designation' out of 'pass_oacc_device_lower'

[OpenACC] Extract 'pass_oacc_loop_designation' out of 'pass_oacc_device_lower'

This really is a separate step -- and another pass to be added between the two,
later on.

	gcc/
	* omp-offload.c (oacc_loop_xform_head_tail, oacc_loop_process):
	'update_stmt' after modification.
	(pass_oacc_loop_designation): New function, extracted out of...
	(pass_oacc_device_lower): ... this.
	(pass_data_oacc_loop_designation, pass_oacc_loop_designation)
	(make_pass_oacc_loop_designation): New
	* passes.def: Add it.
	* tree-parloops.c (create_parallel_loop): Adjust.
	* tree-pass.h (make_pass_oacc_loop_designation): New.
	gcc/testsuite/
	* c-c++-common/goacc/classify-kernels-unparallelized.c:
	's%oaccdevlow%oaccloops%g'.
	* c-c++-common/goacc/classify-kernels.c: Likewise.
	* c-c++-common/goacc/classify-parallel.c: Likewise.
	* c-c++-common/goacc/classify-routine-nohost.c: Likewise.
	* c-c++-common/goacc/classify-routine.c: Likewise.
	* c-c++-common/goacc/classify-serial.c: Likewise.
	* c-c++-common/goacc/routine-nohost-1.c: Likewise.
	* g++.dg/goacc/template.C: Likewise.
	* gcc.dg/goacc/loop-processing-1.c: Likewise.
	* gfortran.dg/goacc/classify-kernels-unparallelized.f95: Likewise.
	* gfortran.dg/goacc/classify-kernels.f95: Likewise.
	* gfortran.dg/goacc/classify-parallel.f95: Likewise.
	* gfortran.dg/goacc/classify-routine-nohost.f95: Likewise.
	* gfortran.dg/goacc/classify-routine.f95: Likewise.
	* gfortran.dg/goacc/classify-serial.f95: Likewise.
	* gfortran.dg/goacc/routine-multiple-directives-1.f90: Likewise.
	libgomp/
	* testsuite/libgomp.oacc-c-c++-common/pr85486-2.c:
	's%oaccdevlow%oaccloops%g'.
	* testsuite/libgomp.oacc-c-c++-common/pr85486-3.c: Likewise.
	* testsuite/libgomp.oacc-c-c++-common/pr85486.c: Likewise.
	* testsuite/libgomp.oacc-c-c++-common/routine-nohost-1.c:
	Likewise.
	* testsuite/libgomp.oacc-c-c++-common/vector-length-128-1.c:
	Likewise.
	* testsuite/libgomp.oacc-c-c++-common/vector-length-128-2.c:
	Likewise.
	* testsuite/libgomp.oacc-c-c++-common/vector-length-128-3.c:
	Likewise.
	* testsuite/libgomp.oacc-c-c++-common/vector-length-128-4.c:
	Likewise.
	* testsuite/libgomp.oacc-c-c++-common/vector-length-128-5.c:
	Likewise.
	* testsuite/libgomp.oacc-c-c++-common/vector-length-128-6.c:
	Likewise.
	* testsuite/libgomp.oacc-c-c++-common/vector-length-128-7.c:
	Likewise.
	* testsuite/libgomp.oacc-fortran/routine-nohost-1.f90: Likewise.

Co-Authored-By: Julian Brown <julian@codesourcery.com>
Co-Authored-By: Kwok Cheung Yeung <kcy@codesourcery.com>