Fix issue with 32bit build for row-mt=1

This patch fix the issue resulting in multi-threading
mismatch for row-mt=1, 32bit build and 64x64 SB size.

BUG=aomedia:2361

Change-Id: I6fd999024e729b3a6d874cd06685388b88547e35

av1/encoder/partition_strategy.c

diff --git a/av1/encoder/partition_strategy.c b/av1/encoder/partition_strategy.c
index 4ea5b16..ba011f1 100644
--- a/av1/encoder/partition_strategy.c
+++ b/av1/encoder/partition_strategy.c
@@ -146,6 +146,7 @@
     return;
   }
 
+  aom_clear_system_state();
   const NN_CONFIG *nn_config = NULL;
   const float *ml_mean = NULL, *ml_std = NULL;
   float split_only_thresh = 10.0f, no_split_thresh = -10.0f;