dct4x4_test: add missing avx2 functions

exercises the forward transforms
no idct/iht implementations, so the c-code is used

Change-Id: I88c11ac37ac6456de9b4b3ec5da059faf4ad6066

test/fdct4x4_test.cc

@@ -376,4 +376,19 @@ INSTANTIATE_TEST_CASE_P(
         make_tuple(&vp9_fht4x4_sse2, &vp9_iht4x4_16_add_sse2, 3)));
 #endif
 
+#if HAVE_AVX2
+INSTANTIATE_TEST_CASE_P(
+    AVX2, Trans4x4DCT,
+    ::testing::Values(
+        make_tuple(&vp9_fdct4x4_avx2,
+                   &vp9_idct4x4_16_add_c, 0)));
+INSTANTIATE_TEST_CASE_P(
+    AVX2, Trans4x4HT,
+    ::testing::Values(
+        make_tuple(&vp9_fht4x4_avx2, &vp9_iht4x4_16_add_c, 0),
+        make_tuple(&vp9_fht4x4_avx2, &vp9_iht4x4_16_add_c, 1),
+        make_tuple(&vp9_fht4x4_avx2, &vp9_iht4x4_16_add_c, 2),
+        make_tuple(&vp9_fht4x4_avx2, &vp9_iht4x4_16_add_c, 3)));
+#endif
+
 }  // namespace