Upstream added a new backtrace-suppression kunit test module that builds
by default with CONFIG_KUNIT_TEST, so add it to the list of kunit common
modules.
Fixes: bbc960d009 ("kunit: Add backtrace suppression self-tests")
Change-Id: I954b297b363b229d7458aabb553077df5cfbe28b
Signed-off-by: Carlos Llamas <cmllamas@google.com>