GL: Silence null dispatch error

These are false positive. We actually want to
not dispatch in this case.

source/blender/gpu/opengl/gl_compute.cc

@@ -16,6 +16,12 @@ void GLCompute::dispatch(int group_x_len, int group_y_len, int group_z_len)
 {
   GL_CHECK_RESOURCES("Compute");
 
+  /* Sometime we reference a dispatch size but we want to skip it by setting one dimension to 0.
+   * Avoid error being reported on some implementation for these case. */
+  if (group_x_len == 0 || group_y_len == 0 || group_z_len == 0) {
+    return;
+  }
+
   glDispatchCompute(group_x_len, group_y_len, group_z_len);
 }