AC-12755 Improve web api async

Author: tranthienbinh1989

app/code/Magento/WebapiAsync/Controller/Rest/Asynchronous/InputParamsResolver.php

@@ -26,6 +26,8 @@
 
 /**
  * This class is responsible for retrieving resolved input data
+ *
+ * @SuppressWarnings(PHPMD.CouplingBetweenObjects)
  */
 class InputParamsResolver
 {
@@ -160,7 +162,7 @@ public function getInputData()
         $inputData = $this->request->getRequestData();
 
         $httpMethod = $this->request->getHttpMethod();
-        if ($httpMethod == RestRequest::HTTP_METHOD_DELETE) {
+        if ($httpMethod === RestRequest::HTTP_METHOD_DELETE) {
             $requestBodyParams = $this->request->getBodyParams();
             $inputData = array_merge($requestBodyParams, $inputData);
         }

dev/tests/api-functional/testsuite/Magento/Quote/Api/GuestCartManagementTest.php

@@ -354,7 +354,7 @@ public function testPlaceOrder()
     public function testAssignCustomerByGuestUser()
     {
         $this->expectException(\Exception::class);
-        $this->expectExceptionMessage('"%fieldName" is required. Enter and try again.');
+        $this->expectExceptionMessage('\"%fieldName\" is required. Enter and try again.');
 
         /** @var $quote \Magento\Quote\Model\Quote */
         $quote = $this->objectManager->create(\Magento\Quote\Model\Quote::class)->load('test01', 'reserved_order_id');