tests: Fix subpass self-dependency and barrier in test

As @ratchetfreak points out, this self-dependency and barrier were
invalid per 6.5.1: "Self-dependencies must only include pipeline stage
bits that are graphics stages".

Signed-off-by: Chris Forbes <chrisforbes@google.com>
diff --git a/tests/layer_validation_tests.cpp b/tests/layer_validation_tests.cpp
index 65adc81..1a2ca52 100644
--- a/tests/layer_validation_tests.cpp
+++ b/tests/layer_validation_tests.cpp
@@ -3132,8 +3132,8 @@
     };
 
     VkSubpassDependency dep = {
-        0, 0, VK_PIPELINE_STAGE_ALL_COMMANDS_BIT,
-        VK_PIPELINE_STAGE_ALL_COMMANDS_BIT,
+        0, 0, VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT,
+        VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT,
         VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT,
         VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT,
         VK_DEPENDENCY_BY_REGION_BIT
@@ -3206,8 +3206,8 @@
         { VK_IMAGE_ASPECT_COLOR_BIT, 0, 1, 0, 1 }
     };
     vkCmdPipelineBarrier(m_commandBuffer->handle(),
-                         VK_PIPELINE_STAGE_ALL_COMMANDS_BIT,
-                         VK_PIPELINE_STAGE_ALL_COMMANDS_BIT,
+                         VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT,
+                         VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT,
                          VK_DEPENDENCY_BY_REGION_BIT,
                          0, nullptr, 0, nullptr, 1, &imb);