[analyzer] restructure var flags so we can store usage count; restrict TEnumParameter propagation to usage == 1
[analyzer] restructure var flags so we can store usage count; restrict TEnumParameter propagation to usage == 1

pleclech/hacking-haxe,pleclech/hacking-haxe,pleclech/hacking-haxe,pleclech/hacking-haxe,pleclech/hacking-haxe,pleclech/hacking-haxe