Add Rust wrapper for tombstoned client using cxx.

Bug: 226162295
Test: atest libtombstoned_client_rust_test
Change-Id: Ibe7c41e2381f0f369a76175d6f71fc60b71cc7d5
diff --git a/debuggerd/TEST_MAPPING b/debuggerd/TEST_MAPPING
index d5327db..efc13df 100644
--- a/debuggerd/TEST_MAPPING
+++ b/debuggerd/TEST_MAPPING
@@ -2,6 +2,9 @@
   "presubmit": [
     {
       "name": "debuggerd_test"
+    },
+    {
+      "name": "libtombstoned_client_rust_test"
     }
   ]
 }