Refactor the code so that logging level can be included.

Bug: b/144093703
Change-Id: I266384b7f971109214ae8d435209478ba705bc66
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/40951
Kokoro-Presubmit: kokoro <noreply+kokoro@google.com>
Reviewed-by: Alexis Hétu <sugoi@google.com>
Tested-by: Ben Clayton <bclayton@google.com>