Fix compatibility

Author: ondrejmirtes

src/Reflection/Php/BuiltinMethodReflection.php

@@ -36,8 +36,6 @@ public function isPrivate(): bool;
 
 	public function isPublic(): bool;
 
-	public function isConstructor(): bool;
-
 	public function getPrototype(): self;
 
 	public function isDeprecated(): TrinaryLogic;

src/Reflection/Php/FakeBuiltinMethodReflection.php

@@ -79,11 +79,6 @@ public function isPublic(): bool
 		return true;
 	}
 
-	public function isConstructor(): bool
-	{
-		return false;
-	}
-
 	public function getPrototype(): BuiltinMethodReflection
 	{
 		throw new \ReflectionException();

src/Reflection/Php/PhpClassReflectionExtension.php

@@ -562,7 +562,8 @@ private function createMethod(
 		$isInternal = false;
 		$isFinal = false;
 		if (
-			$methodReflection->isConstructor()
+			$methodReflection instanceof NativeBuiltinMethodReflection
+			&& $methodReflection->isConstructor()
 			&& $declaringClass->getFileName() !== false
 		) {
 			foreach ($methodReflection->getParameters() as $parameter) {