Fix BufferView access tests for scaled types

Fix BufferView access tests for scaled types

The way in which these tests were written assumes the input and output
to the shaders are of the same type; however, for scaled types they are
converted from integral to floating point before being processed in the
shader. This change corrects that issue as well as adds the two missing
scaled types to the framework.

Affected tests:
dEQP-VK.api.buffer_view.access.uniform_texel_buffer.*

VK-GL-CTS Issue: 4239

Components: Vulkan

Change-Id: I84f904648c6f2cf301111250dba28feabf782788
(cherry picked from commit 9145d71d6f8461c23af15ae09d8e846279270f44)