Adds support for emitting print locations when using the Subzero
backend. Very useful for debugging.

Bug: b/149572931
Change-Id: I32fc14486cd7a021f424fb926dc776072374b931
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/41288Tested-by: Antonio Maiorano <amaiorano@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>