[llvm] [openmp] [OpenMP] Fix runtimes default build (PR #149871)

[Madhur Amilkanthwar via llvm-commits]

madhur13490 wrote:

> > via `LLVM_ENABLE_PROJECTS`.
> 
> In this case the Clang build tree and the openmp build tree are identical. Fixed in #151117.
> 
> Note that this build mode is deprecated since #136314. Consider moving to a runtimes build. According to the warning message added in #136314, that build mode should already have been removed.

Thanks for all the help. We switched to `ENABLE_RUNTIMES` in our CI and we're back to green. 

https://github.com/llvm/llvm-project/pull/149871