rtc: Apply condition to avoid blk_skip for non-screen

This is a follow-up to:
https://aomedia-review.googlesource.com/c/aom/+/174561

Although the artifact was observed for screen content,
the same condition should apply to non-screen.

Stats changed overall small and neutral for video
speeds 7 - 10.

Change-Id: I196f0bf3e51eb717f40135eff2bc718c8566f2c9

av1/encoder/nonrd_opt.c

diff --git a/av1/encoder/nonrd_opt.c b/av1/encoder/nonrd_opt.c
index 5783ee6..499e994 100644
--- a/av1/encoder/nonrd_opt.c
+++ b/av1/encoder/nonrd_opt.c
@@ -829,11 +829,10 @@
   }
   pd->dst = *orig_dst;
 
-  // TODO(marpan): This is to remove bad artifact observed under screen.
+  // TODO(marpan): This is to remove bad visual artifact.
   // For now avoid use of the blk_skip feature (set in block_yrd),
   // unless it's spatially flat or stationary block.
-  if (cpi->oxcf.tune_cfg.content == AOM_CONTENT_SCREEN &&
-      x->source_variance > 0 &&
+  if (x->source_variance > 0 &&
       x->content_state_sb.source_sad_nonrd != kZeroSad)
     allow_blk_skip = 0;