Add description to test cases in tests/kernel/mem_heap,
tests/kernel/mem_slab and tests/kernel/mem_pool
Signed-off-by: Spoorthi K <spoorthi.k@intel.com>
For many tests, avoid splitting into files and put eveything in main.c.
For many of the tests, use main.c as the test source file to keep things
consistent.
Signed-off-by: Anas Nashif <anas.nashif@intel.com>
