[llvm] WIP: [Offload] Add testing for Offload program and kernel related entry points (PR #127803)

[Joseph Huber via llvm-commits]

jhuber6 wrote:

> @jhuber6 I've addressed some of your comments on here on the original PR (#122106). After fixing an issue with the __tgt_device_image lifetime I've realised I no longer need the plugin changes, so I'd like to roll these two PRs into one, since having reviews split across both is confusing. I'll close this PR soon and move the changes across.

That really needs to be fixed regardless, registering an image with the runtime should do a copy of all the data.

https://github.com/llvm/llvm-project/pull/127803