Both LLVM and Subzero now support it, so there's no need to expose this as a capability. Yay!

Bug: b/142132927
Change-Id: I5cf5eece809f7305d38e8d0f995be45d44a8b1cd
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/38449Tested-by: Ben Clayton <bclayton@google.com>
Reviewed-by: Alexis Hétu <sugoi@google.com>
Kokoro-Presubmit: kokoro <noreply+kokoro@google.com>