ac: eliminate duplicated VS exports

ac: eliminate duplicated VS exports

Only very few shaders have them (from 48486 shaders):

shaders/private/left_4_dead_2/765.shader_test - ac: 1 matches 2
shaders/private/left_4_dead_2/877.shader_test - ac: 1 matches 6
shaders/private/left_4_dead_2/2141.shader_test - ac: 1 matches 6
shaders/private/ue4_effects_cave/11.shader_test - ac: 4 matches 5
shaders/private/ue4_effects_cave/14.shader_test - ac: 5 matches 6
shaders/private/ue4_effects_cave/46.shader_test - ac: 5 matches 6
shaders/private/ue4_effects_cave/42.shader_test - ac: 4 matches 5
shaders/private/ue4_effects_cave/104.shader_test - ac: 4 matches 5
shaders/private/f1-2015/336.shader_test - ac: 3 matches 4
shaders/private/f1-2015/948.shader_test - ac: 6 matches 7
shaders/private/f1-2015/602.shader_test - ac: 0 matches 3
shaders/private/f1-2015/600.shader_test - ac: 0 matches 3
shaders/private/f1-2015/1214.shader_test - ac: 0 matches 1
shaders/private/f1-2015/988.shader_test - ac: 4 matches 5
shaders/private/ue4_elemental/149.shader_test - ac: 3 matches 4
shaders/private/ue4_elemental/346.shader_test - ac: 4 matches 5
shaders/private/ue4_elemental/178.shader_test - ac: 3 matches 4
shaders/private/ue4_elemental/136.shader_test - ac: 4 matches 5
shaders/private/ue4_elemental/168.shader_test - ac: 4 matches 5
shaders/private/ue4_elemental/690.shader_test - ac: 3 matches 4
shaders/private/ue4_elemental/19.shader_test - ac: 5 matches 6
shaders/private/dota2/1901.shader_test - ac: 0 matches 5
shaders/private/dota2/1357.shader_test - ac: 0 matches 5
shaders/private/dota2/1375.shader_test - ac: 0 matches 5
shaders/private/dota2/1369.shader_test - ac: 0 matches 5
shaders/private/dota2/1583.shader_test - ac: 0 matches 5
shaders/private/dota2/1811.shader_test - ac: 0 matches 5
shaders/private/dota2/1893.shader_test - ac: 0 matches 5
shaders/private/dota2/1533.shader_test - ac: 0 matches 5
shaders/private/dota2/1951.shader_test - ac: 0 matches 5
shaders/private/dota2/1361.shader_test - ac: 0 matches 5
shaders/private/mad_max/2792.shader_test - ac: 0 matches 1
shaders/private/mad_max/2794.shader_test - ac: 0 matches 1
shaders/private/mad_max/2780.shader_test - ac: 0 matches 1
shaders/private/mad_max/2902.shader_test - ac: 0 matches 1
shaders/private/bioshock-infinite/3050.shader_test - ac: 3 matches 7
shaders/private/bioshock-infinite/2544.shader_test - ac: 3 matches 6
shaders/private/bioshock-infinite/3062.shader_test - ac: 3 matches 8
shaders/private/bioshock-infinite/2012.shader_test - ac: 3 matches 7
shaders/private/bioshock-infinite/3058.shader_test - ac: 3 matches 7
shaders/private/bioshock-infinite/3270.shader_test - ac: 3 matches 7
shaders/private/bioshock-infinite/732.shader_test - ac: 3 matches 7
shaders/private/bioshock-infinite/3026.shader_test - ac: 3 matches 7
shaders/private/bioshock-infinite/3258.shader_test - ac: 3 matches 6
shaders/private/bioshock-infinite/3198.shader_test - ac: 3 matches 6
shaders/private/bioshock-infinite/3046.shader_test - ac: 3 matches 7
shaders/private/bioshock-infinite/3168.shader_test - ac: 3 matches 6
shaders/private/bioshock-infinite/2550.shader_test - ac: 3 matches 6
shaders/private/bioshock-infinite/3210.shader_test - ac: 3 matches 6
shaders/private/bioshock-infinite/3032.shader_test - ac: 3 matches 6
shaders/private/bioshock-infinite/668.shader_test - ac: 3 matches 7

Reviewed-by: Dave Airlie <airlied@redhat.com>
Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>