Remove special ANS initialization handling

Change-Id: I5d5a93b27a42d591ff41ff23c007fc2954d2f9a7
diff --git a/test/ans_test.cc b/test/ans_test.cc
index a553a9e..fd460f4 100644
--- a/test/ans_test.cc
+++ b/test/ans_test.cc
@@ -51,7 +51,8 @@
 
 bool check_rabs(const PvVec &pv_vec, uint8_t *buf) {
   BufAnsCoder a;
-  aom_buf_ans_alloc(&a, NULL, kBufAnsSize);
+  a.size = kBufAnsSize;
+  aom_buf_ans_alloc(&a, NULL);
   buf_ans_write_init(&a, buf);
 
   std::clock_t start = std::clock();
@@ -125,7 +126,8 @@
 bool check_rans(const std::vector<int> &sym_vec, const rans_sym *const tab,
                 uint8_t *buf) {
   BufAnsCoder a;
-  aom_buf_ans_alloc(&a, NULL, kBufAnsSize);
+  a.size = kBufAnsSize;
+  aom_buf_ans_alloc(&a, NULL);
   buf_ans_write_init(&a, buf);
   aom_cdf_prob dec_tab[kRansSymbols];
   rans_build_dec_tab(tab, dec_tab);