WIP: test dual_source_blending

Author: ErichDonGubler

cts_runner/test.lst

@@ -385,7 +385,7 @@ webgpu:shader,validation,expression,overload_resolution:*
 webgpu:shader,validation,extension,clip_distances:*
 webgpu:shader,validation,extension,dual_source_blending:blend_src_same_type:*
 webgpu:shader,validation,extension,dual_source_blending:blend_src_stage_input_output:*
-webgpu:shader,validation,extension,dual_source_blending:blend_src_syntax_validation:*
+webgpu:shader,validation,extension,dual_source_blending:*
 webgpu:shader,validation,extension,dual_source_blending:use_blend_src_requires_extension_enabled:*
 webgpu:shader,validation,extension,pointer_composite_access:*
 webgpu:shader,validation,functions,restrictions:param_type_can_be_alias:*