[IR] Stop deleting other signatures of User::operator new when we override one...

[IR] Stop deleting other signatures of User::operator new when we override one signature in a class derived from User

User has 3 signatures for operator new today. They take a single size, a size and a number of users, and a size, number of users, and descriptor size.

Historically there used to only be one signature that took size and a number of uses. Long ago derived classes implemented their own versions that took just a size and would call the size and use count version. Then they left an unimplemented signature for the size and use count signature from User. As we moved to C++11 this unimplemented signature because = delete.

Since then operator new has picked up two new signatures for operator new. But when the 3 argument version was added it was never added to the delete list in all of the derived classes where the 2 argument version is deleted. This makes things inconsistent.

I believe once one version of operator new is created in a derived class name hiding will take care of making all of the base class signatures unavailable. So I don't think the deleted lines are needed at all.

This patch removes all of the deletes in cases where there is an override or there is already a delete of another signature (that should trigger name hiding too).

Differential Revision: https://reviews.llvm.org/D34120

llvm-svn: 305251