extract_imports and extract_memories do push_memory duplicated inModule::instantiate

[yjhmelody]

When building module, memory is collected by both imports and memories now.

What I means Memory::new is called twice when there is only one import "env" "memory".
The first one is called by me for pass it to linker, but the second one is called by extract_memories.
But if we do not import memory, Memory::new never be called.

[Robbepop]

Sorry but I don't understand at all what exactly the problem is supposed to be here.
Can you please provide a .wat file example or (preferably) paste some .wat code that does not work as intended?

[yjhmelody]

Ok, I will add a test to show it.

[yjhmelody]

See #589

[yjhmelody]

Hi @Robbepop Could you give me some feedback?

[Robbepop]

Sorry, my initial answer was wrong, so I deleted it again, then I forgot to write another. I wrote a new answer as review comment to your PR.