Specify buffers in some calls of dlog_tests

Specify buffers in some calls of dlog_tests

Those tests would start failing on some targets after the libdlogutil
patches. This would be due to them trying to clear/get size of the apps
buffer, which does not exist. This was accepted before the libdlogutil
patches, because dlogutil would consider all of the enabled buffers at
the same time. However, said patches change it to clear/get size of each
buffer separately and return on the first failure. We can work around
this issue by making it so that dlogutil will not try to manipulate the
apps buffer in the failing spots.

Change-Id: I5b3135256b99b0bc8f53a14fc68f99a9effbf6c3