with-meta should return identity when new meta is identical to prior

For persistent objects, if meta is identical, with-meta should return the identical object rather than replacing meta and returning a new object.

Like https://clojure.atlassian.net/browse/CLJ-2362#icft=CLJ-2362 but for ClojureScript.

For example,

now evaluates to true in Clojure 1.10.0-alpha5.

I suspect this can be achieved by updating all of pertinent IWithMeta implementations in cljs.core to be like the following revision for PersistentVector

while also dealing with the trick that vec and set employ when using with-meta to force a new object to be created (see CLJS-2442).