[llvm] Revert "Add HexagonGlobalScheduler pass (#180803)" (PR #181418)

[Brian Cain via llvm-commits]

androm3da wrote:

> > [d0252a1](https://github.com/llvm/llvm-project/commit/d0252a1013e26a80204e723b0b0aaecfdc3b601a) could fix some (or all if we're lucky) of the problem(s) introduced
> 
> If I revert my patch, then this patch also needs to be reverted, right?

No - my commit never landed.  That commit is from my fork (github treats all the forks as one big commit soup).  I was about to pull the trigger on a PR when I saw this revert.  Probably for the best to go ahead w/the revert for now.

https://github.com/llvm/llvm-project/pull/181418