[OpenMP][NFC] Simplify targetDataEnd conditions for CopyMember
targetDataEnd and targetDataBegin compute CopyMember/copy differently,
and I don't see why they should. This patch eliminates one of those
differences by making a simplifying NFC change to targetDataEnd.
The change is NFC as follows. The change only affects the case when
`!UNIFIED_SHARED_MEMORY || HasCloseModifier`. In that case, the
following points are always true:
* The value of CopyMember is relevant later only if DelEntry = false.
* DelEntry = false only if one of the following is true:
* IsLast = false. In this case, it's always true that CopyMember
= false = IsLast.
* `MEMBER_OF && !PTR_AND_OBJ` is true. In this case, CopyMember =
IsLast.
* Thus, if CopyMember is relevant, CopyMember = IsLast.
Reviewed By: grokos
Differential Revision: https://reviews.llvm.org/D105990