Synchronize clears and reads in transient attachment tests

Synchronize clears and reads in transient attachment tests

These tests use a render pass with no draw operations to clear a color
or depth/stencil attachment and use it as an input attachment in a
second render pass, but they were missing a barrier to synchronize both
operations.

Affected tests:
dEQP-VK.fragment_operations.transient_attachment_bit*

Components: Vulkan
VK-GL-CTS issue: 3717

Change-Id: Ifcd1817fa631973e4f74866546dfad4e021a16bc