Handle auto-fdo 0 more carefully

Handle auto-fdo 0 more carefully

This patch fixes few other places where auto-fdo 0 should be be treated as
actual 0 (i.e. probably never executed).  Overall I think we should end up
combining static profile with auto-fdo profile where auto-fdo has 0 counts,
but that is something that should be benchmarked and first it is neccessary to
get something benchmarkeable out of auto-FDO.

gcc/ChangeLog:

	* cgraph.cc (cgraph_edge::maybe_hot_p): For auto-fdo turn 0
	to non-zero.
	* ipa-cp.cc (cs_interesting_for_ipcp_p): Do not trust
	auto-fdo 0.
	* profile-count.cc (profile_count::adjust_for_ipa_scaling): Likewise.
	(profile_count::from_gcov_type): Fix formating.