[llvm] [LLVM] Add environment triple for 'llvm' (PR #117218)

[Petr Hosek via llvm-commits]

================
@@ -299,8 +299,9 @@ class Triple {
     OpenHOS,
 
     PAuthTest,
+    LLVM,
----------------
petrhosek wrote:

I'd put it right after `MuslX32` since it logically belongs in that block.

https://github.com/llvm/llvm-project/pull/117218