dicttoolkit: pin cpp_std to gnu++17

This project doesn't build with gnu++20 and prevents AOSP default to be
upgraded to a newer standard. Once the build failure is fixed here, this
change can be reverted.

Bug: 311052584
Test: m checkbuild
Change-Id: If2d19c1b6d970703a1dbf7685588a4a4be5a53c1

Author: Tomasz Wasilczyk

native/dicttoolkit/Android.bp

@@ -24,6 +24,7 @@ package {
 cc_defaults {
     name: "dicttoolkit_defaults",
 
+    cpp_std: "gnu++17",
     cflags: [
         "-Werror",
         "-Wall",