Use C++20 in libinput

This is needed to support features like default comparators.

Bug: 217165277
Bug: 216232380
Test: atest inputflinger_tests
Change-Id: Ifb8b074678e87b56271b207c1806d8b41b1ee9e9
diff --git a/services/inputflinger/tests/Android.bp b/services/inputflinger/tests/Android.bp
index aae4e0d..9d200bd 100644
--- a/services/inputflinger/tests/Android.bp
+++ b/services/inputflinger/tests/Android.bp
@@ -58,7 +58,7 @@
         ],
     },
     static_libs: [
-        "libc++fs"
+        "libc++fs",
     ],
     require_root: true,
     test_suites: ["device-tests"],