Optimilization the method datastoreNormalizedNodeToCompositeNode

Origin method used schema context (which isn't necessary) and additionaly
doesn't cover all cases. + fixing of incorrect corresponding tests

Change-Id: Idbead2696de9102a202cad03c78f4a1a14a2d1d3
Signed-off-by: Jozef Gloncak <jgloncak@cisco.com>
Merge "Optimilization the method datastoreNormalizedNodeToCompositeNode"