fix deqp reference texture lookup not adhearing to the ES2.0 spec language

fix deqp reference texture lookup not adhearing to the ES2.0 spec language

"If the magnification filter is given by LINEAR and the minification
filter is given by NEAREST_MIPMAP_NEAREST or NEAREST_MIPMAP_LINEAR,
then c = 0.5. This is done to ensure that a minified texture does not
appear “sharper” than a magnified texture. Otherwise c = 0"

This was removed in ES3.0

The reference rasterizer is ES3, so it needs to get the version of the
device under test (DUT) and change its behaviour acordingly

Components: GLES2

VK-GL-CTS issue: #890

Affects:
dEQP-GLES2.functional.texture.filtering.2d.nearest_mipmap_nearest_linear_clamp_rgba8888
dEQP-GLES2.functional.texture.filtering.2d.nearest_mipmap_nearest_linear_repeat_rgba8888
dEQP-GLES2.functional.texture.filtering.2d.nearest_mipmap_nearest_linear_mirror_rgba8888
dEQP-GLES2.functional.texture.filtering.2d.nearest_mipmap_linear_linear_clamp_rgba8888
dEQP-GLES2.functional.texture.filtering.2d.nearest_mipmap_linear_linear_repeat_rgba8888
dEQP-GLES2.functional.texture.filtering.2d.nearest_mipmap_linear_linear_mirror_rgba8888
dEQP-GLES2.functional.texture.filtering.2d.nearest_mipmap_nearest_linear_repeat_etc1
dEQP-GLES2.functional.texture.filtering.2d.nearest_mipmap_nearest_linear_mirror_etc1
dEQP-GLES2.functional.texture.filtering.2d.nearest_mipmap_linear_linear_repeat_etc1
dEQP-GLES2.functional.texture.filtering.2d.nearest_mipmap_linear_linear_mirror_etc1
dEQP-GLES2.functional.texture.vertex.cube.filtering.nearest_mipmap_nearest_linear_clamp
dEQP-GLES2.functional.texture.vertex.cube.filtering.nearest_mipmap_nearest_linear_repeat
dEQP-GLES2.functional.texture.vertex.cube.filtering.nearest_mipmap_nearest_linear_mirror
dEQP-GLES2.functional.texture.vertex.cube.filtering.nearest_mipmap_linear_linear_clamp
dEQP-GLES2.functional.texture.vertex.cube.filtering.nearest_mipmap_linear_linear_repeat
dEQP-GLES2.functional.texture.vertex.cube.filtering.nearest_mipmap_linear_linear_mirror

Change-Id: I43024a13e0f63eb929da60d02c9722900c46506c