Cherry-pick 58895ed. rdar://122778867

    AX: Missing _prepareAccessibilityCall in accessibilityIsInNonNativeTextControl
    https://bugs.webkit.org/show_bug.cgi?id=269214
    rdar://122778867

    Reviewed by Andres Gonzalez.

    We need to add a _prepareAccessibilityCall to avoid a nullptr dereference.

    * Source/WebCore/accessibility/ios/WebAccessibilityObjectWrapperIOS.mm:
    (-[WebAccessibilityObjectWrapper accessibilityIsInNonNativeTextControl]):

    Canonical link: https://commits.webkit.org/274497@main

Identifier: 272448.542@safari-7618.1.15.14-branch

Source/WebCore/accessibility/ios/WebAccessibilityObjectWrapperIOS.mm

@@ -2762,6 +2762,9 @@ - (BOOL)accessibilityIsDeletion
 
 - (BOOL)accessibilityIsInNonNativeTextControl
 {
+    if (![self _prepareAccessibilityCall])
+        return NO;
+
     return !!Accessibility::findAncestor(*self.axBackingObject, true, [] (const auto& object) {
         return object.isNonNativeTextControl();
     });