Rename canonicalize into two functions:

* canonicalize_replace_cache
* canonicalize_replace_client

Now it is clear at the call site that if there are
duplicate copies of the data between the cache and
the caller, which copy gets replaced.

Additionally data parameter is now const-correct.
If it is not going to be replaced (canonicalize_replace_cache),
then the shared_ptr to the client data is const.

src/ripple/nodestore/impl/DatabaseShardImp.cpp

@@ -892,7 +892,7 @@ DatabaseShardImp::store(
     auto [backend, pCache, nCache] = shard->getBackendAll();
     auto nObj {NodeObject::createObject(type, std::move(data), hash)};
 
-    pCache->canonicalize(hash, nObj, true);
+    pCache->canonicalize_replace_cache(hash, nObj);
     backend->store(nObj);
     nCache->erase(hash);