[llvm] [Offload] Lazily initialize platforms in the Offloading API (PR #163272)

[Joseph Huber via llvm-commits]

jhuber6 wrote:

> Any chance that this is causing http://45.33.8.238/macm1/115570/step_10.txt ?
> 
> Am I holding something wrong?
> 
> (Linux/x64 seems to be happy.)

Completely unrelated

https://github.com/llvm/llvm-project/pull/163272