test/Makefile: Refactor the Makefile

The Makefile for test is not efficient and reads bad. We have to
specify the name for each test 2 times (filename and name without
the ext) while we could have just elided the extension from the
source filename.

Let's make it simpler and easier to manage.

Changes summary:
 - Clean up and reorder things.
 - Sort the `test_srcs` alphabetically.
 - Remove `test_objs` (it turned out unused).
 - Generate `test_targets` variable from `test_srcs` by simply
   removing the `.c` and `.cc` file extension.

Signed-off-by: Ammar Faizi <ammar.faizi@students.amikom.ac.id>
Link: https://lore.kernel.org/r/20211030114858.320116-3-ammar.faizi@intel.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
1 file changed