Annotate inner loops in "acc kernels loop" directives (C/C++).

Annotate inner loops in "acc kernels loop" directives (C/C++).

Normally explicit loop directives in a kernels region inhibit
automatic annotation of other loops in the same nest, on the theory
that users have indicated they want manual control over that section
of code.  However there seems to be an expectation in user code that
the combined "kernels loop" directive should still allow annotation of
inner loops.  This patch implements this behavior for C and C++.

2020-08-19  Sandra Loosemore  <sandra@codesourcery.com>

	gcc/c-family/
	* c-omp.cc (annotate_loops_in_kernels_regions): Process inner
	loops in combined "acc kernels loop" directives.

	gcc/testsuite/
	* c-c++-common/goacc/kernels-loop-annotation-18.c: New.
	* c-c++-common/goacc/kernels-loop-annotation-19.c: New.
	* c-c++-common/goacc/combined-directives.c: Adjust expected
	patterns.