layer: Add in-use validation for imageView

Bind imageView from a descriptor to the command buffer at CmdBindDescriptorSets
time and check for an in-use imageView at DestroyImageView time.

Also use new AddCommandBufferBindingImageView() helper to bind children of
framebuffer in AddFrameBufferBinding().
diff --git a/layers/descriptor_sets.cpp b/layers/descriptor_sets.cpp
index df5dac2..f02da6b 100644
--- a/layers/descriptor_sets.cpp
+++ b/layers/descriptor_sets.cpp
@@ -880,9 +880,7 @@
     // Add binding for image
     auto iv_state = getImageViewState(dev_data, image_view_);
     if (iv_state) {
-        auto image_node = getImageNode(dev_data, iv_state->create_info.image);
-        if (image_node)
-            core_validation::AddCommandBufferBindingImage(dev_data, cb_node, image_node);
+        core_validation::AddCommandBufferBindingImageView(dev_data, cb_node, iv_state);
     }
 }
 
@@ -913,9 +911,7 @@
     // Add binding for image
     auto iv_state = getImageViewState(dev_data, image_view_);
     if (iv_state) {
-        auto image_node = getImageNode(dev_data, iv_state->create_info.image);
-        if (image_node)
-            core_validation::AddCommandBufferBindingImage(dev_data, cb_node, image_node);
+        core_validation::AddCommandBufferBindingImageView(dev_data, cb_node, iv_state);
     }
 }