BUG: Usage of aliases is not generating correct code

[JanMichaelPeter]

Describe the bug
A bug was reported to me that when a library is imported under an alias, the code-generation is not using this alias.

To Reproduce
Steps to reproduce the behavior, e.g.:

1. Create new Driver
2. Import a library to the driver using an alias. e.g. import '../../constants.dart' as foo;
3. Use the alias in code e.g.: 'foo.SomeClass get class => ...'
4. Run the generator to generate the test driver
5. Observe that code was not generated using the alias

Expected behavior
If I import stuff using an alias, the code generator should also use the alias

[ebajrami]

Fixed with #187