spirv_new: fix test_decorate. (#1980)

test_decorate was checking for half-precision NAN incorrectly, calling
cl_half_from_float where cl_half_to_float was intended, causing a wrong
expected result.

test_decorate was also printing the expected and actual results
reversed, printing "got -1, want 0", when our implementation already
returned 0.

test_conformance/spirv_new/test_decorate.cpp

@@ -229,7 +229,7 @@ static inline To compute_saturated_output(Ti lhs, Ti rhs)
  f = cl_half_to_float(cl_half_from_float(f, CL_HALF_RTE));
 
  To val = (To)std::min<float>(std::max<float>(f, loVal), hiVal);
- if (isnan(cl_half_from_float(rhs, CL_HALF_RTE)))
+ if (isnan(cl_half_to_float(rhs)))
  {
  val = 0;
  }
@@ -309,7 +309,7 @@ int verify_saturated_results(cl_device_id deviceID, cl_context context,
 
  if (val != h_res[i])
  {
- log_error("Value error at %d: got %d, want %d\n", i, val, h_res[i]);
+ log_error("Value error at %d: got %d, want %d\n", i, h_res[i], val);
  return -1;
  }
  }