LazyCachedNode parent reference causes memory leak

The changes made for MODE-1613, seem to be causing a memory leak inside LazyCachedNode causing nodes from the workspace cache to not be collected by the GC.

One possible explanation is the following: the parentReferenceToSelfParent is a CachedNode reference, which, in the case of a parent - child relationship, would cause the parent to still be referenceable even after being evicted/removed from the cache, as long as at least one of the referencing children is still cached.