diagnostics: avoid using global_dc in path-printing

gcc/analyzer/ChangeLog:
	* checker-path.cc (checker_path::debug): Explicitly use
	global_dc's reference printer.
	* diagnostic-manager.cc
	(diagnostic_manager::prune_interproc_events): Likewise.
	(diagnostic_manager::prune_system_headers): Likewise.

gcc/ChangeLog:
	* diagnostic-path.cc (diagnostic_event::get_desc): Add param
	"ref_pp" and use instead of global_dc.
	(class path_label): Likewise, adding field m_ref_pp.
	(event_range::event_range): Add param "ref_pp" and pass to
	m_path_label.
	(path_summary::path_summary): Add param "ref_pp" and pass to
	event_range ctor.
	(diagnostic_text_output_format::print_path): Pass *pp to
	path_summary ctor.
	(selftest::test_empty_path): Pass *event_pp to pass_summary ctor.
	(selftest::test_intraprocedural_path): Likewise.
	(selftest::test_interprocedural_path_1): Likewise.
	(selftest::test_interprocedural_path_2): Likewise.
	(selftest::test_recursion): Likewise.
	(selftest::test_control_flow_1): Likewise.
	(selftest::test_control_flow_2): Likewise.
	(selftest::test_control_flow_3): Likewise.
	(selftest::assert_cfg_edge_path_streq): Likewise.
	(selftest::test_control_flow_5): Likewise.
	(selftest::test_control_flow_6): Likewise.
	* diagnostic-path.h (diagnostic_event::get_desc): Add param
	"ref_pp".
	* lazy-diagnostic-path.cc (selftest::test_intraprocedural_path):
	Pass *event_pp to get_desc.
	* simple-diagnostic-path.cc (selftest::test_intraprocedural_path):
	Likewise.

Signed-off-by: David Malcolm <dmalcolm@redhat.com>