Encoder/Decoder mismatch fix: need a separate copy of eob_counts.

The bug was introduced here:
https://chromium-review.googlesource.com/#/c/399975/4/av1/encoder/bitstream.c
In that patch, I had removed 2nd declaration of a variable of the same
name. But it turns out that the two variables actually had a different
type (even though the name was same).

Now, we keep both variables, but rename one of them -- that fixes the
mismatch. While we are at it, made both variables local as well.

The fix can be verified as follows:
../../libvpx/configure --enable-experimental --enable-supertx
--enable-var-tx --enable-entropy --enable-internal-stats && make clean
&& make -j16

aomenc -o soccer_cif_1000_av1_b8.webm ../soccer_cif.y4m --codec=av1
--limit=50 --skip=0 -p 2 --pass=1 --fpf=soccer_cif_av1.fpf --good
--cpu-used=0 --target-bitrate=1000 --lag-in-frames=25 --min-q=0
--max-q=63 --auto-alt-ref=1 --kf-max-dist=150 --kf-min-dist=0
--drop-frame=0 --static-thresh=0 --bias-pct=50 --minsection-pct=0
--maxsection-pct=2000 --arnr-maxframes=7 --arnr-strength=5 --sharpness=0
--undershoot-pct=100 --overshoot-pct=100 --frame-parallel=0
--tile-columns=0 --profile=0 --test-decode=warn

aomenc -o soccer_cif_1000_av1_b8.webm ../soccer_cif.y4m --codec=av1
--limit=50 --skip=0 -p 2 --pass=2 --fpf=soccer_cif_av1.fpf --good
--cpu-used=0 --target-bitrate=1000 --lag-in-frames=25 --min-q=0
--max-q=63 --auto-alt-ref=1 --kf-max-dist=150 --kf-min-dist=0
--drop-frame=0 --static-thresh=0 --bias-pct=50 --minsection-pct=0
--maxsection-pct=2000 --arnr-maxframes=7 --arnr-strength=5 --sharpness=0
--undershoot-pct=100 --overshoot-pct=100 --frame-parallel=0
--tile-columns=0 --profile=0 --test-decode=warn -v --psnr

Change-Id: Ibd72dbe1f620e6de231513220ee4e190606613ae

av1/encoder/bitstream.c

diff --git a/av1/encoder/bitstream.c b/av1/encoder/bitstream.c
index a4bd8d9..743d10b 100644
--- a/av1/encoder/bitstream.c
+++ b/av1/encoder/bitstream.c
@@ -2478,8 +2478,6 @@
 #if CONFIG_ENTROPY
   AV1_COMMON *cm = &cpi->common;
   SUBFRAME_STATS *subframe_stats = &cpi->subframe_stats;
-  unsigned int eob_counts_copy[TX_SIZES][PLANE_TYPES][REF_TYPES][COEF_BANDS]
-                              [COEFF_CONTEXTS];
   int i;
   av1_coeff_probs_model dummy_frame_coef_probs[PLANE_TYPES];
 
@@ -2504,8 +2502,10 @@
 #if CONFIG_ENTROPY
       if (cm->do_subframe_update &&
           cm->refresh_frame_context == REFRESH_FRAME_CONTEXT_BACKWARD) {
+        unsigned int this_eob_counts_copy[PLANE_TYPES][REF_TYPES][COEF_BANDS]
+                                         [COEFF_CONTEXTS];
         av1_coeff_count coef_counts_copy[PLANE_TYPES];
-        av1_copy(eob_counts_copy, cpi->common.counts.eob_branch[tx_size]);
+        av1_copy(this_eob_counts_copy, cpi->common.counts.eob_branch[tx_size]);
         av1_copy(coef_counts_copy, cpi->td.rd_counts.coef_counts[tx_size]);
         build_tree_distribution(cpi, tx_size, frame_branch_ct,
                                 frame_coef_probs);
@@ -2517,7 +2517,7 @@
           build_tree_distribution(cpi, tx_size, cpi->branch_ct_buf[i][tx_size],
                                   dummy_frame_coef_probs);
         }
-        av1_copy(cpi->common.counts.eob_branch[tx_size], eob_counts_copy);
+        av1_copy(cpi->common.counts.eob_branch[tx_size], this_eob_counts_copy);
         av1_copy(cpi->td.rd_counts.coef_counts[tx_size], coef_counts_copy);
 
         update_coef_probs_subframe(w, cpi, tx_size, cpi->branch_ct_buf,
@@ -2545,6 +2545,8 @@
   av1_copy(subframe_stats->coef_probs_buf[0], cm->fc->coef_probs);
   if (cm->do_subframe_update &&
       cm->refresh_frame_context == REFRESH_FRAME_CONTEXT_BACKWARD) {
+    unsigned int eob_counts_copy[TX_SIZES][PLANE_TYPES][REF_TYPES][COEF_BANDS]
+                                [COEFF_CONTEXTS];
     av1_copy(eob_counts_copy, cm->counts.eob_branch);
     for (i = 1; i <= cpi->common.coef_probs_update_idx; ++i) {
       for (tx_size = TX_4X4; tx_size <= max_tx_size; ++tx_size)