Add tests and test images

Author: morsssss

ext/gd/tests/imagecreatefromstring_avif.phpt

@@ -0,0 +1,29 @@
+--TEST--
+imagecreatefromstring() - AVIF format
+--EXTENSIONS--
+gd
+--SKIPIF--
+<?php
+  if (!(imagetypes() & IMG_AVIF)) {
+    die('skip AVIF support required');
+  }
+?>
+--FILE--
+<?php
+echo "Reading image whose major brand is 'avif':\n";
+$im = imagecreatefromstring(file_get_contents(__DIR__ . '/imagecreatefromstring_major_brand.avif'));
+var_dump(imagesx($im));
+var_dump(imagesy($im));
+
+echo "Reading image with a compatible brand that's 'avif':\n";
+$im = imagecreatefromstring(file_get_contents(__DIR__ . '/imagecreatefromstring_compatible_brand.avif'));
+var_dump(imagesx($im));
+var_dump(imagesy($im));
+?>
+--EXPECT--
+Reading image whose major brand is 'avif':
+int(250)
+int(375)
+Reading image with a compatible brand that's 'avif':
+int(480)
+int(270)

ext/gd/tests/imagecreatefromstring_compatible_brand.avif

@@ -39,6 +39,19 @@ array(16) {
     ["mime"]=>
     string(9) "image/bmp"
   }
+  ["test1pix.avif"]=>
+  array(5) {
+    [0]=>
+    int(0)
+    [1]=>
+    int(0)
+    [2]=>
+    int(19)
+    [3]=>
+    string(20) "width="0" height="0""
+    ["mime"]=>
+    string(10) "image/avif"
+  }
   ["test12pix.webp"]=>
   array(6) {
     [0]=>