Safe pixelpipe caching for dt_dev_pixelpipe_process()

If we have this called with pipe->type having the DT_DEV_PIXELPIPE_IMAGE bit set
as called from dt_dev_image() we don't want to use the pipe cache but instead do simple
2-buffer swapping.

sdvsd

src/develop/pixelpipe_cache.c

@@ -87,7 +87,7 @@ void dt_dev_pixelpipe_cache_cleanup(struct dt_dev_pixelpipe_t *pipe)
 {
   dt_dev_pixelpipe_cache_t *cache = &(pipe->cache);
 
-  if(pipe->type & DT_DEV_PIXELPIPE_FULL)
+  if(pipe->type == DT_DEV_PIXELPIPE_FULL)
   {
     dt_print(DT_DEBUG_PIPE, "Session fullpipe cache report. hits/run=%.2f, hits/test=%.3f\n",
     (double)(cache->hits) / fmax(1.0, pipe->runs),

src/develop/pixelpipe_hb.c

@@ -2633,7 +2633,7 @@ gboolean dt_dev_pixelpipe_process(
            const int devid)
 {
   pipe->processing = TRUE;
-  pipe->nocache = FALSE;
+  pipe->nocache = (pipe->type & DT_DEV_PIXELPIPE_IMAGE) != 0;
   pipe->runs++;
   pipe->opencl_enabled = dt_opencl_running();