Use precompiled Gitaly binaries in gitlab/tmp/tests

Overview

When running specs in gitlab/ with GDK, Gitaly still compiles during setup, even if skip_compile: true is configured in GDK.

We can improve this by adding precompiled Gitaly binaries to the gitlab/tmp/tests folder. This removes the need for local compilation and speeds up test runs.

Impacted categories

The following categories relate to this issue:

• gdk-reliability - e.g. When a GDK action fails to complete.
• gdk-usability - e.g. Improvements or suggestions around how the GDK functions.
• gdk-performance - e.g. When a GDK action is slow or times out.