Always use toLLVM() to avoid a compiler warning / error that the function was declared by never used.

Fix the arguments passed to the DebugInfo constructor.

Change-Id: I1df069c028c9bfcf1f8e7f4221ffffd4f0261069
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/34329
Kokoro-Presubmit: kokoro <noreply+kokoro@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>
Tested-by: Ben Clayton <bclayton@google.com>