[clang] [Clang][OpenMP] Fix `if` clause not affecting `teams` construct (PR #207444)

[Jan André Reuter via cfe-commits]

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Thyre wrote:

`if(...)` should be tested via the non `openmp52` test (see e.g. [here](https://github.com/llvm/llvm-project/blob/d4cf0c375dadd830c27a2b16e0283c4e31beac1a/clang/test/OpenMP/target_teams_distribute_parallel_for_simd_if_codegen.cpp#L66)). The same clauses are present there, and no changes on the emitted IR were necessary.

`if(teams: ...)` should fail for OpenMP v5.1 and lower. For OpenMP v4.5 (and the LLVM default), this is checked in e.g.: https://github.com/llvm/llvm-project/blob/d4cf0c375dadd830c27a2b16e0283c4e31beac1a/clang/test/OpenMP/target_teams_distribute_if_messages.cpp#L70

https://github.com/llvm/llvm-project/pull/207444