Add more tests covering deprecation of _ as CE name

Author: Girgias

Zend/tests/enum/enum_underscore_as_name.phpt

@@ -0,0 +1,18 @@
+--TEST--
+Using "_" as a enum name is deprecated
+--FILE--
+<?php
+
+namespace Foo\Bar {
+    enum _ {}
+}
+
+namespace {
+    enum _ {}
+}
+
+?>
+--EXPECTF--
+Deprecated: Using "_" as a class name is deprecated since 8.4 in %s on line %d
+
+Deprecated: Using "_" as a class name is deprecated since 8.4 in %s on line %d

Zend/tests/interface_underscore_as_name.phpt

@@ -0,0 +1,18 @@
+--TEST--
+Using "_" as an interface name is deprecated
+--FILE--
+<?php
+
+namespace Foo\Bar {
+    interface _ {}
+}
+
+namespace {
+    interface _ {}
+}
+
+?>
+--EXPECTF--
+Deprecated: Using "_" as a class name is deprecated since 8.4 in %s on line %d
+
+Deprecated: Using "_" as a class name is deprecated since 8.4 in %s on line %d

Zend/tests/traits/enum_underscore_as_name.phpt

@@ -0,0 +1,18 @@
+--TEST--
+Using "_" as a trait name is deprecated
+--FILE--
+<?php
+
+namespace Foo\Bar {
+    trait _ {}
+}
+
+namespace {
+    trait _ {}
+}
+
+?>
+--EXPECTF--
+Deprecated: Using "_" as a class name is deprecated since 8.4 in %s on line %d
+
+Deprecated: Using "_" as a class name is deprecated since 8.4 in %s on line %d