Remove hippopotamus.interlaced.png "wuffs test"

Coverage now comes from build-all.sh's nia-checksums-of-data.txt test.
diff --git a/test/c/std/png.c b/test/c/std/png.c
index 2491d5e..95d50eb 100644
--- a/test/c/std/png.c
+++ b/test/c/std/png.c
@@ -182,29 +182,13 @@
 test_wuffs_png_decode_interface() {
   CHECK_FOCUS(__func__);
   wuffs_png__decoder dec;
-
-  {
-    CHECK_STATUS("initialize",
-                 wuffs_png__decoder__initialize(
-                     &dec, sizeof dec, WUFFS_VERSION,
-                     WUFFS_INITIALIZE__LEAVE_INTERNAL_BUFFERS_UNINITIALIZED));
-    CHECK_STRING(do_test__wuffs_base__image_decoder(
-        wuffs_png__decoder__upcast_as__wuffs_base__image_decoder(&dec),
-        "test/data/bricks-gray.png", 0, SIZE_MAX, 160, 120, 0xFF060606));
-  }
-
-  {
-    CHECK_STATUS("initialize",
-                 wuffs_png__decoder__initialize(
-                     &dec, sizeof dec, WUFFS_VERSION,
-                     WUFFS_INITIALIZE__LEAVE_INTERNAL_BUFFERS_UNINITIALIZED));
-    CHECK_STRING(do_test__wuffs_base__image_decoder(
-        wuffs_png__decoder__upcast_as__wuffs_base__image_decoder(&dec),
-        "test/data/hippopotamus.interlaced.png", 0, SIZE_MAX, 36, 28,
-        0xFFF5F5F5));
-  }
-
-  return NULL;
+  CHECK_STATUS("initialize",
+               wuffs_png__decoder__initialize(
+                   &dec, sizeof dec, WUFFS_VERSION,
+                   WUFFS_INITIALIZE__LEAVE_INTERNAL_BUFFERS_UNINITIALIZED));
+  return do_test__wuffs_base__image_decoder(
+      wuffs_png__decoder__upcast_as__wuffs_base__image_decoder(&dec),
+      "test/data/bricks-gray.png", 0, SIZE_MAX, 160, 120, 0xFF060606);
 }
 
 const char*  //