Fix synchronization in compressed texture sampling tests

Fix synchronization in compressed texture sampling tests

Tests sampling compressed textures contained multiple synchronization
errors, most of them related to:

* Render pass load operations not properly synchronized with previous
  writes.
* Barriers that did not properly synchronize all layers of a cube map.
* Improper initial layout transitions.

Affected tests:
dEQP-VK.image.sample_texture.*
dEQP-VKSC.image.sample_texture.*

VK-GL-CTS issue: 3763
Components: Vulkan

Change-Id: I2f2572a7f6a05c55c904014fafc3a655dbb03ee3