static-constant-class-folding

此优化将替换编译时的类常量值:

class MyClass
{
    const SOME_CONSTANT = 100;
    public function getValue()
    {
        return self::SOME_CONSTANT;
    }
}

转换为:

class MyClass
{
    const SOME_CONSTANT = 100;
    public function getValue()
    {
        return 100;
    }
}