SPV: Add SPIRV-Tools validator. This needs the latest SPIR-Tools.

Test/baseResults/hlsl.buffer.frag.out

@@ -145,6 +145,10 @@ gl_FragCoord origin is upper left
 0:?     '@entryPointOutput.a' (layout( location=0) out 4-component vector of float)
 0:?     'input' ( in 4-component vector of float FragCoord)
 
+error: SPIRV-Tools Validation Errors
+error: Structure id 50 decorated as BufferBlock for variable in Uniform storage class must follow standard storage buffer layout rules: member 7 at offset 128 overlaps previous member ending at offset 171
+  %tbufName = OpTypeStruct %v4float %int %float %float %float %float %float %float %mat3v4float %mat3v4float %mat3v4float %mat3v4float
+
 // Module Version 10000
 // Generated by (magic number): 80007
 // Id's are bound by 73