Sync frida-gum typings with Frida 12.6.17 (#37780)

Also improve the type definition for Java.cast().

Changelog at:

        https://www.frida.re/news/2019/05/28/frida-12-6-released/

types/frida-gum/index.d.ts

@@ -1,4 +1,4 @@
-// Type definitions for non-npm package frida-gum 14.0
+// Type definitions for non-npm package frida-gum 14.1
 // Project: https://github.com/frida/frida
 // Definitions by: Ole André Vadla Ravnås <https://github.com/oleavr>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
@@ -3859,6 +3859,13 @@ declare namespace Java {
      */
     function choose(className: string, callbacks: ChooseCallbacks): void;
 
+    /**
+     * Duplicates a JavaScript wrapper for later use outside replacement method.
+     *
+     * @param handle An existing wrapper retrieved from `this` in replacement method.
+     */
+    function retain(obj: Wrapper): Wrapper;
+
     /**
      * Creates a JavaScript wrapper given the existing instance at `handle` of
      * given class `klass` as returned from `Java.use()`.
@@ -3866,7 +3873,7 @@ declare namespace Java {
      * @param handle An existing wrapper or a JNI handle.
      * @param klass Class wrapper for type to cast to.
      */
-    function cast(handle: any, klass: Wrapper): Wrapper;
+    function cast(handle: Wrapper | NativePointerValue, klass: Wrapper): Wrapper;
 
     /**
      * Creates a Java array with elements of the specified `type`, from a