tests: add new kernel objects tests

Found out that important requirements are not tested by current
kernel objects tests. Decided to fix that situation

New added tests:
1. test_kobj_assign_perms_on_alloc_obj()
Create kernel object semaphore, dynamically allocate it from the
calling thread's resource pool.
Check that object's address is in bounds of that memory pool.
Then check the requestor thread will implicitly be assigned
permission on the allocated object by using
semaphore API k_sem_init()

2. test_no_ref_dyn_kobj_release_mem()
Dynamically allocated kernel objects whose access is controlled by
the permission system will use object permission as a reference count
If no threads have access to an object, the object's memory released.

3. test_krnl_obj_static_alloc_build_time()
Take addresses of the kernel objects which are statically allocated
during the build time and verify that they are not null.
That kernel objects shouldn't require manual
registration by the end user.

4. Clean-up. Removed unused variable from userspace test.

Signed-off-by: Maksim Masalski <maksim.masalski@intel.com>