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

Test/baseResults/hlsl.structbuffer.atomics.frag.out

@@ -473,6 +473,10 @@ gl_FragCoord origin is upper left
 0:?     '@entryPointOutput' (layout( location=0) out 4-component vector of float)
 0:?     'pos' (layout( location=0) flat in uint)
 
+error: SPIRV-Tools Validation Errors
+error: AtomicIAdd: expected Value to be of type Result Type
+  %28 = OpAtomicIAdd %uint %24 %uint_1 %uint_0 %int_1
+
 // Module Version 10000
 // Generated by (magic number): 80007
 // Id's are bound by 87