[spirv] Add interpolation tests on non-struct parameters (#681)

tools/clang/test/CodeGenSPIRV/spirv.interpolation.hlsl

@@ -34,6 +34,35 @@ struct PSInput {
   nointerpolation      bool3 bool_d: BOOLD;
 };
 
-float4 main(PSInput input) : SV_Target {
+float4 main(                     PSInput input,
+                                 float   fp_a: FPA1,
+            linear               float1  fp_b: FPB1,
+// CHECK: OpDecorate %in_var_FPC1 Centroid
+            centroid             float2  fp_c: FPC1,
+// CHECK: OpDecorate %in_var_FPD1 Flat
+            nointerpolation      float3  fp_d: FPD1,
+// CHECK: OpDecorate %in_var_FPE1 NoPerspective
+            noperspective        float4  fp_e: FPE1,
+// CHECK: OpDecorate %in_var_FPF1 Sample
+            sample               float   fp_f: FPF1,
+// CHECK: OpDecorate %in_var_FPG1 NoPerspective
+// CHECK: OpDecorate %in_var_FPG1 Sample
+            noperspective sample float2  fp_g: FPG1,
+
+// CHECK: OpDecorate %in_var_INTA1 Flat
+                                 int    int_a: INTA1,
+// CHECK: OpDecorate %in_var_INTD1 Flat
+            nointerpolation      int3   int_d: INTD1,
+
+// CHECK: OpDecorate %in_var_UINTA1 Flat
+                                 uint   uint_a: UINTA1,
+// CHECK: OpDecorate %in_var_UINTD1 Flat
+            nointerpolation      uint3  uint_d: UINTD1,
+
+// CHECK: OpDecorate %in_var_BOOLA1 Flat
+                                 bool   bool_a: BOOLA1,
+// CHECK: OpDecorate %in_var_BOOLD1 Flat
+            nointerpolation      bool3  bool_d: BOOLD1
+           ) : SV_Target {
   return 1.0;
 }