Add a regression test for GH-10008

Author: nielsdos

ext/opcache/tests/opt/gh10008.phpt

@@ -0,0 +1,27 @@
+--TEST--
+GH-10008 (Narrowing occurred during type inference of ZEND_ADD_ARRAY_ELEMENT)
+--INI--
+opcache.enable=1
+opcache.enable_cli=1
+opcache.optimization_level=0x20
+--EXTENSIONS--
+opcache
+--FILE--
+<?php
+function test()
+{
+    $bool_or_int = true;
+    while (a()) {
+        if ($bool_or_int !== true) {
+            // The following line (no longer) triggers narrowing during type inference of ZEND_ADD_ARRAY_ELEMENT.
+            $string_key = "a";
+            $array = ["bool_or_int" => $bool_or_int, $string_key => 123];
+        }
+
+        $bool_or_int = 0;
+    }
+}
+?>
+OK
+--EXPECT--
+OK