test/AV1ResolutionChange: call Next after SetSize

After reallocating SetSize() does not call FillFrame(), deferring that
until the call to Next(). Fixes uninitialized data warnings, but may
hide the assertion failure reported in 3348.

Bug: chromium:1378601
Bug: aomedia:3348
Fixed: aomedia:3350
Change-Id: I2e539e7290726e8061b115a095c0f302e471c57b
(cherry picked from commit 6fcb3bec011cf37ce070b10ded9e3113657de131)

test/frame_size_tests.cc

diff --git a/test/frame_size_tests.cc b/test/frame_size_tests.cc
index d2012df..20aea31 100644
--- a/test/frame_size_tests.cc
+++ b/test/frame_size_tests.cc
@@ -140,6 +140,7 @@
     const aom_codec_cx_pkt_t *pkt;
 
     for (int i = 0; i < kNumFramesPerResolution; ++i) {
+      video.Next();  // SetSize() does not call FillFrame().
       EXPECT_EQ(aom_codec_encode(enc.get(), video.img(), video.pts(),
                                  video.duration(), /*flags=*/0),
                 AOM_CODEC_OK);
@@ -155,7 +156,6 @@
         }
         frame_count++;
       }
-      video.Next();
     }
   }