[AutoDiscover] Use typehinting on PHP7

Currently AutoDiscover is not using typehint feature from PHP7. The main problem is that currently SoapServer is returning empty resposnse and status code 202 Accepted.

My service class:

class MyService
{
    /**
     * @param string $x
     * @return string
     */
    public function test(string $x): string
    {
        return $x;
    }
}

Expected

<definitions xmlns="http://schemas.xmlsoap.org/wsdl/" xmlns:wsdl="http://schemas.xmlsoap.org/wsdl/"
             xmlns:tns="http://localhost/api/My" xmlns:soap="http://schemas.xmlsoap.org/wsdl/soap/"
             xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:soap-enc="http://schemas.xmlsoap.org/soap/encoding/"
             xmlns:soap12="http://schemas.xmlsoap.org/wsdl/soap12/" name="MyService"
             targetNamespace="http://localhost/api/My">
    <types>
        <xsd:schema targetNamespace="http://localhost/api/My"/>
    </types>
    <portType name="MyServicePort">
        <operation name="test">
            <documentation>test</documentation>
            <input message="tns:testIn"/>
            <output message="tns:testOut"/>
        </operation>
    </portType>
    <binding name="MyServiceBinding" type="tns:MyServicePort">
        <soap:binding style="rpc" transport="http://schemas.xmlsoap.org/soap/http"/>
        <operation name="test">
            <soap:operation soapAction="http://localhost/api/My#test"/>
            <input>
                <soap:body use="encoded" encodingStyle="http://schemas.xmlsoap.org/soap/encoding/"
                           namespace="http://localhost/api/My"/>
            </input>
            <output>
                <soap:body use="encoded" encodingStyle="http://schemas.xmlsoap.org/soap/encoding/"
                           namespace="http://localhost/api/My"/>
            </output>
        </operation>
    </binding>
    <service name="MyServiceService">
        <port name="MyServicePort" binding="tns:MyServiceBinding">
            <soap:address location="http://localhost/api/My"/>
        </port>
    </service>
    <message name="testIn">
        <part name="x" type="xsd:string"/>
    </message>
    <message name="testOut">
        <part name="return" type="xsd:string"/>
    </message>
</definitions>

Actual

<definitions xmlns="http://schemas.xmlsoap.org/wsdl/" xmlns:wsdl="http://schemas.xmlsoap.org/wsdl/"
             xmlns:tns="http://localhost/api/My" xmlns:soap="http://schemas.xmlsoap.org/wsdl/soap/"
             xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:soap-enc="http://schemas.xmlsoap.org/soap/encoding/"
             xmlns:soap12="http://schemas.xmlsoap.org/wsdl/soap12/" name="MyService"
             targetNamespace="http://localhost/api/My">
    <types>
        <xsd:schema targetNamespace="http://localhost/api/My"/>
    </types>
    <portType name="MyServicePort">
        <operation name="test">
            <documentation>test</documentation>
            <input message="tns:testIn"/>
        </operation>
    </portType>
    <binding name="MyServiceBinding" type="tns:MyServicePort">
        <soap:binding style="rpc" transport="http://schemas.xmlsoap.org/soap/http"/>
        <operation name="test">
            <soap:operation soapAction="http://localhost/api/My#test"/>
            <input>
                <soap:body use="encoded" encodingStyle="http://schemas.xmlsoap.org/soap/encoding/"
                           namespace="http://localhost/api/My"/>
            </input>
        </operation>
    </binding>
    <service name="MyServiceService">
        <port name="MyServicePort" binding="tns:MyServiceBinding">
            <soap:address location="http://localhost/api/My"/>
        </port>
    </service>
    <message name="testIn">
        <part name="x" type="xsd:anyType"/>
    </message>
</definitions>

zendframework / zend-soap

[AutoDiscover] Use typehinting on PHP7 #58