[clang] [llvm] [OpenACC] Switch Clang to use the Flang 'appertainment' rules for cla… (PR #135372)

[Erich Keane via llvm-commits]

erichkeane wrote:

> Updated list:
> 
> ```
> Disagreements on 'num_gangs' appearing >1x on kernels/kernels-loop (justification for kernels-loop should apply to kernels as well?) (UNK way forward right now)
>     Clang :: SemaOpenACC/compute-construct-num_gangs-clause.c
>   
> FLANG: prohibits device_num >1x  (UNK way forward RN).
>   Clang :: SemaOpenACC/init-construct.cpp
>   Clang :: SemaOpenACC/shutdown-construct.cpp
>   
> Disagreement on 'bind' on a 'routine'. (UNK way forward right now)
>    Clang :: SemaOpenACC/routine-construct-clauses.cpp
> ```

In discussion, we decided that `bind` probably should follow the same rules as "Implemented proposed change for 'routine' gang/worker/vector/seq. (see issue 539)".  So I'll follow-up on that after this.  

https://github.com/llvm/llvm-project/pull/135372