swresample/swresample-test: Randomly wipe out channel counts

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
(cherry picked from commit ff50b1b1)
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libswresample/swresample-test.c

@@ -314,6 +314,11 @@ int main(int argc, char **argv){
             fprintf(stderr, "Failed to init backw_ctx\n");
             return 1;
         }
+        if (uint_rand(rand_seed) % 3 == 0)
+            av_opt_set_int(forw_ctx, "ich", 0, 0);
+        if (uint_rand(rand_seed) % 3 == 0)
+            av_opt_set_int(forw_ctx, "och", 0, 0);
+
         if(swr_init( forw_ctx) < 0)
             fprintf(stderr, "swr_init(->) failed\n");
         if(swr_init(backw_ctx) < 0)