Minor ipa-modref tweaks

Minor ipa-modref tweaks

To make dumps easier to read modref now dumps cgraph_node name rather then
cfun name in function being analysed and I also fixed minor issue with ECF
flags merging when updating inline summary.

gcc/ChangeLog:

2021-11-26  Jan Hubicka  <hubicka@ucw.cz>

	* ipa-modref.c (analyze_function): Drop parameter F and dump
	cgraph node name rather than cfun name.
	(modref_generate): Update.
	(modref_summaries::insert):Update.
	(modref_summaries_lto::insert):Update.
	(pass_modref::execute):Update.
	(ipa_merge_modref_summary_after_inlining): Improve combining of
	ECF_FLAGS.