Track arguments pointing to local or readonly memory in ipa-fnsummary

Track arguments pointing to local or readonly memory in ipa-fnsummary

this patch implement tracking wehther argument points to readonly memory. This
is is useful for ipa-modref as well as for inline heuristics.  It is desirable
to inline functions that dereference pointers to local variables in order
to support SRA.  We always did the oposite heuristics (guessing that the
dereferences will be optimized out with 50% probability) but here we could
increase the probability for cases where we can track that argument is indeed
a local memory (or readonly which is also good)

	* ipa-fnsummary.c (dump_ipa_call_summary): Dump
	points_to_local_or_readonly_memory flag.
	(analyze_function_body): Compute points_to_local_or_readonly_memory
	flag.
	(remap_edge_change_prob): Rename to ...
	(remap_edge_params): ... this one; update
	points_to_local_or_readonly_memory.
	(remap_edge_summaries): Update.
	(read_ipa_call_summary): Stream the new flag.
	(write_ipa_call_summary): Likewise.
	* ipa-predicate.h (struct inline_param_summary): Add
	points_to_local_or_readonly_memory.
	(inline_param_summary::equal_to): Update.
	(inline_param_summary::useless_p): Update.