drop_deinit forwards ownership while effectively stripping the deinitializer. It is similar to a type cast.
Fixes rdar://125590074 ([NonescapableTypes] Nonescapable types
cannot have deinits)
Mirror isIdentityPreservingRefCase.
I don't know why this does not apply to boxes and existentials, but am convervatively staying consistent with the
current behavior.
These instructions carry lifetime dependence from a single operand to a single result. They are not forwarding
instructions because we use them to indicate the boundaries of a forwarded lifetime.
* add ForwardingInstruction conformances to missing forwarding instruction classes
* move all the forwarding instruction conformance definitions into ForwardingInstructions.swift
* remove the default implementations of the requirements, so that every instruction needs to specify them
This instruction was given forwarding ownership in the original OSSA
implementation. That will obviously lead to memory leaks. Remove
ownership from this instruction and verify that it is never used for
non-trivial types.
