Allow to use '$this->pointcutName' in pointcuts with dynamic aspect inheritance

[lisachenko]

Currently, pointcut can be referenced only by full name:

    /**
     * Pointcut for example class
     *
     * @Pointcut("execution(public Demo\Example\General->*(*))")
     */
    protected function examplePublicMethods() {}

    /**
     * Method that should be called before real method
     *
     * @param MethodInvocation $invocation Invocation
     * @Before("Demo\Aspect\DebugAspect->examplePublicMethods")
     */

This prevents from using of abstract pointcuts and make it harder to write FQN of aspect without auto-completion.

New feature allows to use $this instead of FQN of aspect:

    /**
     * Method that should be called before real method
     *
     * @param MethodInvocation $invocation Invocation
     * @Before("$this->examplePublicMethods")
     */