[llvm] [polly] [Support] Remove llvm/Support/Host.h (PR #74261)

[Kazu Hirata via llvm-commits]

kazutakahirata wrote:

> The changes have been made upstream to isl: https://repo.or.cz/isl.git/commitdiff/7ffab9c411283f3e22d39940dd8f57e9ccf497cb?hp=5d5b77e2369434a95d2d66824409b46d2155ba5b

Thanks!  According to `git log -- polly`, it looks like various people have been making search-n-replace-type changes to polly in our repository.

https://github.com/llvm/llvm-project/pull/74261