Use :source-map-timestamp false for REPL evaluation

This is necessary in order to have source maps that do not have ?rel= in
them. This patch needs CLJS-2493.

src/cljs/snapshot/lumo/repl.cljs

@@ -1185,7 +1185,8 @@
     (select-keys @app-opts [:verbose :static-fns :fn-invoke-direct :checked-arrays])
     (if expression?
       (merge {:context :expr
-              :def-emits-var true}
+              :def-emits-var true
+              :source-map-timestamp false}
              (when (and form (load-form? form))
                {:source-map true}))
       {:source-map true})))