Fixed issue where aliases were not being resolved in constructors with deep=True.

>>> import yaml
>>> def test(loader, node):
>>>     return loader.construct_sequence(node, deep=True)
>>> yaml.add_constructor('!test', test)
>>> print(yaml.load("""
- &a [anchored]
- !test [*a]
""")

Expected output: [['anchored'], [['anchored']]]

Output before: [['anchored'], [[]]]