This PR changes how branch and empty nodes are encoded:
The encoding of an empty node is stored at position @ENCODED_EMPTY_NODE_POS of the rlp segment.
For encoding a branch node we write the child encoded values directly to the rlp segment, instead of storing first the values on SEGMENT_TRIE_ENCODED_CHILD
It saves ~2500 cycles with add11_yml.
This PR changes how branch and empty nodes are encoded: