Fix T43596: Refraction BSDF crashes blender on pre-sse4 CPU

This is the same issue T43475: SSE4 code is more robust to non-finite values
in the ray origin/direction. So for now added a check before doing BVH traversal
for pre-SSE4 CPUs.

For sure actual root of the issue is a bit different and much more tricky to
solve, especially without disturbing render results too much. Still looking
into this.

In any case, it's kinda fine to have such a check, we might later make it to be
a kernel_assert() instead of just a return.

intern/cycles/kernel/geom/geom_qbvh_shadow.h

@@ -58,6 +58,12 @@ ccl_device bool BVH_FUNCTION_FULL_NAME(QBVH)(KernelGlobals *kg,
 	Transform ob_tfm;
 #endif
 
+#ifndef __KERNEL_SSE41__
+	if(!isfinite(P.x)) {
+		return false;
+	}
+#endif
+
 #if BVH_FEATURE(BVH_INSTANCING)
 	int num_hits_in_instance = 0;
 #endif

intern/cycles/kernel/geom/geom_qbvh_subsurface.h

@@ -61,6 +61,12 @@ ccl_device uint BVH_FUNCTION_FULL_NAME(QBVH)(KernelGlobals *kg,
 	Transform ob_tfm;
 #endif
 
+#ifndef __KERNEL_SSE41__
+	if(!isfinite(P.x)) {
+		return 0;
+	}
+#endif
+
 	ssef tnear(0.0f), tfar(isect_t);
 	sse3f idir4(ssef(idir.x), ssef(idir.y), ssef(idir.z));
 

intern/cycles/kernel/geom/geom_qbvh_traversal.h

@@ -66,6 +66,12 @@ ccl_device bool BVH_FUNCTION_FULL_NAME(QBVH)(KernelGlobals *kg,
 	Transform ob_tfm;
 #endif
 
+#ifndef __KERNEL_SSE41__
+	if(!isfinite(P.x)) {
+		return false;
+	}
+#endif
+
 	isect->t = ray->t;
 	isect->u = 0.0f;
 	isect->v = 0.0f;

intern/cycles/kernel/geom/geom_qbvh_volume.h

@@ -57,6 +57,12 @@ ccl_device bool BVH_FUNCTION_FULL_NAME(QBVH)(KernelGlobals *kg,
 	Transform ob_tfm;
 #endif
 
+#ifndef __KERNEL_SSE41__
+	if(!isfinite(P.x)) {
+		return false;
+	}
+#endif
+
 	isect->t = ray->t;
 	isect->u = 0.0f;
 	isect->v = 0.0f;

intern/cycles/kernel/geom/geom_triangle_intersect.h

@@ -314,9 +314,6 @@ ccl_device_inline float3 triangle_refine(KernelGlobals *kg,
 
 #ifdef __INTERSECTION_REFINE__
 	if(isect->object != OBJECT_NONE) {
-		if(UNLIKELY(t == 0.0f)) {
-			return P;
-		}
 #ifdef __OBJECT_MOTION__
 		Transform tfm = sd->ob_itfm;
 #else