Igor Matheus Andrade Torrente authored Aug 15, 2020 and Pekka Paalanen committed Sep 05, 2020

Currently doesn't exist a standard way to write a weston.ini inside a test.

Here, two new functions `weston_ini_setup` and `cfgln` are introduced to
help the test writer to write a weston.ini file and load it to the test.
And `internal-screenshot-test` is converted to use the new method of write
a weston.ini. This conversion serves as example and initial API test.

The tester needs to call `weston_test_harness_execute_as_client` or
`weston_test_harness_execute_as_plugin` in the same way as before.
The `weston_ini_setup` will fill the setup->config_file with the
correct path to the weston.ini file.

The main design goal is to avoid pre-made or build-made weston.ini(s)
and keep the test as self-contained as possible.

Closes:#410


Signed-off-by: Igor Matheus Andrade Torrente <igormtorrente@gmail.com>