bindings: python: tests: add a new test case

bindings: python: tests: add a new test case

Add a test-case for line request by name with multiple entries.

Signed-off-by: Chuang Zhu <git@chuang.cz>
[Bartosz:
  - tweak the commit message
  - improve the test class name
  - extend the test assertion to test the 'baz' line too]
Co-developed-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Reviewed-by: Kent Gibson <warthog618@gmail.com>
Link: https://lore.kernel.org/r/20240710125719.33655-3-brgl@bgdev.pl
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>