message: Implement OpQuantizeToF16
diff: #include <math.h>
  #include <time.h>
  #include "common/formatting.h"
  +#include "maths/half_convert.h"
  #include "os/os_specific.h"
  #include "spirv_op_helpers.h"
  @@ -916,6 +917,18 @@ void ThreadState::StepNext(ShaderDebugState *state, const rdcarray<ThreadState>
  SetDst(conv.result, var);
  break;
  }
  + case Op::QuantizeToF16:
  + {
  + OpQuantizeToF16 quant(it);
  +
  + ShaderVariable var = GetSrc(quant.value);
  +
  + for(uint8_t c = 0; c < var.columns; c++)
  + var.value.fv[c] = ConvertFromHalf(ConvertToHalf(var.value.fv[c]));
  +
  + SetDst(quant.result, var);
  + break;
  + }
  case Op::FConvert:
  {
  OpFConvert cast(it);
  