Marl has its own repo and tests now, and so it is excessive to build and run these tests for downstream projects as well.

Bug: b/140546382
Change-Id: Ic79db961a3bfae072a56ffeb7052165c127538d3
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/36112Reviewed-by: Ben Clayton <bclayton@google.com>
Tested-by: Ben Clayton <bclayton@google.com>