aco: add framework for testing isel and integration tests

And add some simple tests to demonstrate/test the pipeline builder and
glsl_scraper.py.

Signed-off-by: Rhys Perry <pendingchaos02@gmail.com>
Acked-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Acked-by: Daniel Schürmann <daniel@schuermann.dev>
Acked-by: Timur Kristóf <timur.kristof@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/3521>
diff --git a/meson.build b/meson.build
index fc6eeca..011b1ec 100644
--- a/meson.build
+++ b/meson.build
@@ -543,6 +543,10 @@
   dep_vulkan = dependency('vulkan')
 endif
 
+if with_vulkan_overlay_layer or with_aco_tests
+  prog_glslang = find_program('glslangValidator')
+endif
+
 _xvmc = get_option('gallium-xvmc')
 if _xvmc == 'true'
   _xvmc = 'enabled'