[clang] [OpenACC] Sema changes for +*&|^ reduction combiner recipes (PR #162740)

[Erich Keane via cfe-commits]

erichkeane wrote:

This will actually have about 20 tests that crash now with the new assert.  I am quite sure I have been messing up my uses of Array Section functions in quite a few places, so I have to put this on pause until I've figured out what I'm doing/what the right way to do stuff with this is.

https://github.com/llvm/llvm-project/pull/162740