ext/soap: Use more accurate return types in implementations of SoapClient::__doRequest()

The do_request() function that calls this methods, assumes that a string is being returned from the method
otherwise it bails out.

However, the default implementation of SoapClient::__doRequest() indicates that it can return null when it
fails to set-up and execute the HTTP SOAP request, but this always results in a SoapFault exception being
thrown, and thus cannot happen in practice.

We need to investigate further if the return type should be changed from ?string to string or not.

Author: Girgias

ext/soap/tests/any.phpt

@@ -33,7 +33,7 @@ class TestSoapClient extends SoapClient {
     $this->server->addFunction('echoAnyElement');
   }
 
-  function __doRequest($request, $location, $action, $version, $one_way = 0): ?string {
+  function __doRequest($request, $location, $action, $version, $one_way = 0): string {
     ob_start();
     $this->server->handle($request);
     $response = ob_get_contents();

ext/soap/tests/bug69280.phpt

@@ -25,7 +25,7 @@ class TestWS extends \SoapClient {
 		);
 	}
 
-	public function __doRequest(string $request, string $location, string $action, int $version, bool $oneWay = false): ?string {
+	public function __doRequest(string $request, string $location, string $action, int $version, bool $oneWay = false): never {
 		die($request);
 	}
 }

ext/soap/tests/bugs/bug28969.phpt

@@ -18,7 +18,7 @@ class LocalSoapClient extends SoapClient {
     $this->server->addFunction('test');
   }
 
-  function __doRequest($request, $location, $action, $version, $one_way = 0): ?string {
+  function __doRequest($request, $location, $action, $version, $one_way = 0): string {
     ob_start();
     $this->server->handle($request);
     $response = ob_get_contents();

ext/soap/tests/bugs/bug29795.phpt

@@ -12,7 +12,7 @@ class LocalSoapClient extends SoapClient {
     parent::__construct($wsdl, $options);
   }
 
-  function __doRequest($request, $location, $action, $version, $one_way = 0): ?string {
+  function __doRequest($request, $location, $action, $version, $one_way = 0): string {
     return <<<EOF
 <?xml version="1.0" encoding="UTF-8"?><SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/"
 xmlns:SOAP-ENC="http://schemas.xmlsoap.org/soap/encoding/"

ext/soap/tests/bugs/bug29839.phpt

@@ -20,7 +20,7 @@ class LocalSoapClient extends SoapClient {
     $this->server->addFunction('EchoString');
   }
 
-  function __doRequest($request, $location, $action, $version, $one_way = 0): ?string {
+  function __doRequest($request, $location, $action, $version, $one_way = 0): string {
     ob_start();
     $this->server->handle($request);
     $response = ob_get_contents();

ext/soap/tests/bugs/bug29844.phpt

@@ -22,7 +22,7 @@ class LocalSoapClient extends SoapClient {
     $this->server->setClass('hello_world');
   }
 
-  function __doRequest($request, $location, $action, $version, $one_way = 0): ?string {
+  function __doRequest($request, $location, $action, $version, $one_way = 0): string {
     ob_start();
     $this->server->handle($request);
     $response = ob_get_contents();

ext/soap/tests/bugs/bug30045.phpt

@@ -21,7 +21,7 @@ class LocalSoapClient extends SoapClient {
     $this->server->addFunction('foo');
   }
 
-  function __doRequest($request, $location, $action, $version, $one_way = 0): ?string {
+  function __doRequest($request, $location, $action, $version, $one_way = 0): string {
     $xml = simplexml_load_string($request);
     echo $xml->children("http://schemas.xmlsoap.org/soap/envelope/")->Body->children("http://test-uri")->children()->param1->asXML(),"\n";
     unset($xml);

ext/soap/tests/bugs/bug30106.phpt

@@ -21,7 +21,7 @@ class LocalSoapClient extends SoapClient {
         $this->server->addFunction("getContinentList");
   }
 
-  function __doRequest($request, $location, $action, $version, $one_way = 0): ?string {
+  function __doRequest($request, $location, $action, $version, $one_way = 0): string {
     echo $request;
     ob_start();
     $this->server->handle($request);

ext/soap/tests/bugs/bug30175.phpt

@@ -9,7 +9,7 @@ soap.wsdl_cache_enabled=0
 
 class LocalSoapClient extends SoapClient {
 
-  function __doRequest($request, $location, $action, $version, $one_way = 0): ?string {
+  function __doRequest($request, $location, $action, $version, $one_way = 0): string {
     return <<<EOF
 <?xml version="1.0" encoding="UTF-8"?>
 <SOAP-ENV:Envelope

ext/soap/tests/bugs/bug30928.phpt

@@ -25,7 +25,7 @@ class LocalSoapClient extends SoapClient {
     $this->server->addFunction('test');
   }
 
-  function __doRequest($request, $location, $action, $version, $one_way = 0): ?string {
+  function __doRequest($request, $location, $action, $version, $one_way = 0): string {
     ob_start();
     $this->server->handle($request);
     $response = ob_get_contents();