BUG: Series.append with DatetimeBlock and DatetimeTZBlock raises AttributeError
Splitted from #11351. `Series.append` with `DatetimeBlock` and `DatetimeTZBlock` raises `AttributeError`.

```
import pandas as pd

s = pd.Series([pd.Timestamp('2011-01-01'), pd.NaT])
s
#0   2011-01-01
#1          NaT
# dtype: datetime64[ns]

stz = pd.Series(pd.DatetimeIndex(['2012-01-01', '2012-01-02'], tz='Asia/Tokyo'))
stz
#0   2012-01-01 00:00:00+09:00
#1   2012-01-02 00:00:00+09:00
# dtype: datetime64[ns, Asia/Tokyo]

s.append(stz)
# AttributeError: 'numpy.ndarray' object has no attribute 'tz_localize'
```
