API: ExtensionArray.argsort places the missing value at the end 
continue #26354 

1. Categorical will be handled in a separate PR.
2. benchmark result:
```
       before           after         ratio
     [989f912e]       [dc0ef701]
     <master>         <enh-21801-2>
+     11.4±0.03μs       36.8±0.1μs     3.23  algorithms.EASorting.time_argsort(1000)
+       785±0.5μs      1.26±0.03ms     1.60  algorithms.EASorting.time_argsort(100000)

```

xref https://github.com/pandas-dev/pandas/issues/21801 (doesn't close; Need to update existing EAs)