Fix #131240: Cycles: Negative integration range in Huang Hair

It is possible that the valid range computed from `theta` and the range
visible to the current pixel do not overlap. In this case the hair
section has no contribution.

Pull Request: https://projects.blender.org/blender/blender/pulls/133337

intern/cycles/kernel/closure/bsdf_principled_hair_huang.h

@@ -875,6 +875,12 @@ ccl_device Spectrum bsdf_hair_huang_eval(KernelGlobals kg,
   bsdf->extra->gamma_m_min = gamma_m_min;
   bsdf->extra->gamma_m_max = gamma_m_max;
 
+  if (!(bsdf->extra->gamma_m_min < bsdf->extra->gamma_m_max)) {
+    /* No overlap between the valid range and the visible range. Can happen at grazing `theta`
+     * angles. */
+    return zero_spectrum();
+  }
+
   const float projected_area = cos_theta(local_I) * dh;
 
   return (bsdf_hair_huang_eval_r(kg, sc, local_I, local_O) +