chore: remove legacy code

This were leftovers from the previous versions when we were reusing
the same DOM node for all popups.

Now we're creating the new DOM node (.swal2-container) for each popup.

src/instanceMethods/_main.js

@@ -149,16 +149,10 @@ const swalPromise = (instance, domCache, innerParams) => {
     // Reverse buttons (Confirm on the right side)
     if (innerParams.reverseButtons) {
       domCache.confirmButton.parentNode.insertBefore(domCache.cancelButton, domCache.confirmButton)
-    } else {
-      domCache.confirmButton.parentNode.insertBefore(domCache.confirmButton, domCache.cancelButton)
     }
 
     addKeydownHandler(instance, globalState, innerParams, dismissWith)
 
-    instance.enableButtons()
-    instance.hideLoading()
-    instance.resetValidationMessage()
-
     if (innerParams.toast && (innerParams.input || innerParams.footer || innerParams.showCloseButton)) {
       dom.addClass(document.body, swalClasses['toast-column'])
     } else {
@@ -188,7 +182,7 @@ const swalPromise = (instance, domCache, innerParams) => {
       }
     }
 
-    // fix scroll
+    // Scroll container to top on open (#1247)
     domCache.container.scrollTop = 0
   })
 }