[ci skip] Add missing oss-fuzz test for 8de697e

Author: ndossche

ext/date/tests/time/duration/methods/oss_fuzz_562721806.phpt

@@ -0,0 +1,12 @@
+--TEST--
+OSS-Fuzz #562721806 (Use-of-uninitialized-value in zim_Time_Duration___unserialize)
+--FILE--
+<?php
+try {
+    unserialize('O:13:"Time\Duration"::{}');
+} catch (Throwable $e) {
+    echo $e::class, ": ", $e->getMessage(), "\n";
+}
+?>
+--EXPECT--
+Exception: Invalid serialization data for Time\Duration object