comparison: Add a mode to not apply filters on interface sub-graphs

comparison: Add a mode to not apply filters on interface sub-graphs

This patch allows to avoid applying filters on interface diff node
sub-graphs because those filters are useful for interface impact
analysis only, which is not needed in the leaf-node report, for
instance.  When using the leaf-node report, this capability speeds up
corpus_diff::apply_filters_and_suppressions_before_reporting, hence
the functions like corpus_diff::{has_incompatible_changes,
has_net_subtype_changes} are sped up too.

That patch thus adds a --no-change-categorization option to abidiff to
avoid doing that change categorization (A.K.A applying filters).

	* doc/manuals/abidiff.rst: Document the new
	--no-change-categorization option.
	* doc/manuals/kmidiff.rst: Likewise.
	* include/abg-comparison.h
	(diff_context::perform_change_categorization): Declare new
	accessor member functions.
	* src/abg-comparison-priv.h
	(diff_context::priv::perform_change_categorization_): Add new data
	member.
	(diff_context::priv::priv): Initialize the new data member.
	* src/abg-comparison.cc
	(diff_context::perform_change_categorization): Define new accessor
	member functions.
	(corpus_diff::priv::apply_filters_and_compute_diff_stats):
	Don't apply filters on the diff node sub-graphs of interfaces when
	the user requested "no change categorization".
	* tools/abidiff.cc (options::perform_change_categorization): New
	data member.
	(options::options): Initialize the new data member.
	(display_usage): Add a help string for the new
	--no-change-categorization.
	(parse_command_line): Parse the new --no-change-categorization
	option.
	(set_diff_context_from_opts): Set the option on the diff context
	here.
	* tools/kmidiff.cc(options::perform_change_categorization): New
	data member.
	(options::options): Initialize the new data member.
	(display_usage): Add a help string for the new
	--no-change-categorization.
	(parse_command_line): Parse the new --no-change-categorization
	option.
	(set_diff_context_from_opts): Set the option on the diff context
	here.

Signed-off-by: Dodji Seketeli <dodji@redhat.com>