message: Use the more accurate DynamicMemoryUsage() when trimming the dbcache
  Previously we were using the inner coins cache usage however this
  does significantly lower the total bytes used which then causes
  us to over trim the cache and with a subsequent lower performance.
diff: @@ -255,7 +255,7 @@ void CCoinsViewCache::Trim(size_t nTrimSize) const
  LOCK(cs_utxo);
  CCoinsMap::iterator iter = cacheCoins.begin();
  - while (cachedCoinsUsage > nTrimSize)
  + while (DynamicMemoryUsage() > nTrimSize)
  {
  if (iter == cacheCoins.end())
  break;
  