Populate RE metadata in ranker verifiable nodes

Summary:
attach re metadata to the verifiable node in ranker.

Surround with JK: https://www.internalfb.com/intern/justknobs/?name=ci_efficiency%2Fcitadel#attach_re_metadata

Differential Revision: D60207094

fbshipit-source-id: 8047c34310b98dd9703a0392e753a02e9ebac4c5

td_util/src/supertd_events.rs

@@ -35,6 +35,7 @@ pub enum Event {
     VERIFIABLE_MATCHER_SUCCESS,
     VERSE_SUCCESS,
     BUILD_DIRECTIVES_SPECIFIED,
+    RE_METADATA_SUCCESS,
 }
 
 /// Initialize the Scuba client for the `supertd_events` dataset.