tests: Build the input file into the initest unit test.

tests: Build the input file into the initest unit test.

This breaks an external dependency and makes the expected command line
conform to the other unit tests. Also get rid of some ancient tests
which test adding to the ini's contents based on command line
arguments.

This test still needs to be modified so that it actually checks whether
what happened was correct.

Change-Id: I2c9ea9fa79781bceb5cd3d1419870924e8bbd45f
Reviewed-on: https://gem5-review.googlesource.com/6081
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>