shader_runner: add ability to specify GL_TEXTURE_MAX_LEVEL

Signed-off-by: Chris Forbes <chrisf@ijw.co.nz>
arb_texture_query_levels: add group and shader-runner dir

Signed-off-by: Chris Forbes <chrisf@ijw.co.nz>
arb_texture_query_levels: add compiler tests for textureQueryLevels()

This tests that all the required signatures exist.

Signed-off-by: Chris Forbes <chrisf@ijw.co.nz>
arb_texture_query_levels: add execution tests

Ensure that the returned level count is correct in various situations.

Signed-off-by: Chris Forbes <chrisf@ijw.co.nz>