Add bug #70957 and #70958 releated test in refection

ext/reflection/tests/ReflectionMethod_defaultArg.phpt

@@ -0,0 +1,44 @@
+--TEST--
+ReflectionMethod and RECV_INIT (bug #70957 and #70958)
+--FILE--
+<?php
+Abstract class F {
+	private function bar($a = self::class) {}
+}
+
+Trait T
+{
+	private function bar($a = self::class) {}
+}
+
+
+class B {
+	use T;
+}
+
+echo new \ReflectionMethod('F', 'bar');
+echo new \ReflectionMethod('T', 'bar');
+echo new \ReflectionMethod('B', 'bar');
+?>
+--EXPECTF--
+Method [ <user> private method bar ] {
+  @@ %s
+
+  - Parameters [1] {
+    Parameter #0 [ <optional> $a = 'F' ]
+  }
+}
+Method [ <user> private method bar ] {
+  @@ %s
+
+  - Parameters [1] {
+    Parameter #0 [ <optional> $a = 'T' ]
+  }
+}
+Method [ <user> private method bar ] {
+  @@ %s
+
+  - Parameters [1] {
+    Parameter #0 [ <optional> $a = 'B' ]
+  }
+}