MQE-818: Enable executeJS to save a variable

- executeJS now assigns a variable for storage.

Author: KevinBKozan

dev/tests/verification/Resources/BasicFunctionalTest.txt

@@ -91,7 +91,7 @@ class BasicFunctionalTestCest
 		$I->dontSeeOptionIsSelected(".functionalTestSelector", "someInput");
 		$I->doubleClick(".functionalTestSelector");
 		$I->dragAndDrop(".functionalTestSelector", ".functionalTestSelector2");
-		$I->executeJS("someJSFunction");
+		$executeJSKey1 = $I->executeJS("someJSFunction");
 		$I->fillField(".functionalTestSelector", "someInput");
 		$I->fillField(".functionalTestSelector", "0");
 		$grabAttributeFromKey1 = $I->grabAttributeFrom(".functionalTestSelector", "someInput");

src/Magento/FunctionalTestingFramework/Util/TestGenerator.php

@@ -959,7 +959,12 @@ public function generateStepsPhp($actionObjects, $hookObject = false, $actor = "
                     $testSteps .= $this->wrapFunctionCall($actor, $actionObject, $function);
                     break;
                 case "executeJS":
-                    $testSteps .= $this->wrapFunctionCall($actor, $actionObject, $function);
+                    $testSteps .= $this->wrapFunctionCallWithReturnValue(
+                        $stepKey,
+                        $actor,
+                        $actionObject,
+                        $function
+                    );
                     break;
                 case "performOn":
                 case "waitForElementChange":