Also remove dependency of third_party/astc-encoder on
src/System/Debug.hpp.

Bug: b/145758253
Change-Id: I329928d9221c99a416fcdb1b0dd44d2578a22cb8
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/43269Reviewed-by: Ben Clayton <bclayton@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>
Tested-by: Antonio Maiorano <amaiorano@google.com>
Kokoro-Presubmit: kokoro <noreply+kokoro@google.com>