[clang] [llvm] Make OpenCL an OSType rather than an EnvironmentType. (PR #170297)

[Matt Arsenault via llvm-commits]

arsenm wrote:

> SPIR-V differences between OpenCL and Vulkan execution environments.

In what way are these different program-visible execution environments? I would hope vendors would implement a common ABI. If there are, I would expect the name to be something reflecting that implementation ABI, not the language? 

e.g., the mistake we made here was having different kernel argument layouts for OpenCL, and later fixed that

https://github.com/llvm/llvm-project/pull/170297