SPV: Fix #1399 emit ImageGatherExtended when using ConstOffsets operand
diff --git a/Test/baseResults/spv.textureGatherBiasLod.frag.out b/Test/baseResults/spv.textureGatherBiasLod.frag.out
index ad79292..faa4dba 100644
--- a/Test/baseResults/spv.textureGatherBiasLod.frag.out
+++ b/Test/baseResults/spv.textureGatherBiasLod.frag.out
@@ -4,6 +4,7 @@
 // Id's are bound by 298
 
                               Capability Shader
+                              Capability ImageGatherExtended
                               Capability SparseResidency
                               Capability SampledCubeArray
                               Capability ImageGatherBiasLodAMD