sadt: Ignore new restriction 'superficial'

In autopkgtest, superficial tests are the opposite of the 'flaky' restriction: if the test fails, it is counted as a failure, but if it succeeds, it is counted as though it had been skipped. This allows autopkgtest to give a different exit status (8 rather than 0) if there is no real evidence that the package works, because every test was either skipped or superficial.

The intention is that trivial smoke tests, such as linking a "hello, world" program to a library without exercising the library's real functionality, can be marked as superficial. See https://bugs.debian.org/904979 for more details. The restriction was originally proposed as "trivial" but was renamed to "superficial" during review.

sadt is a simpler test runner and does not distinguish between successful and skipped tests, so we can treat superficial and non-superficial tests identically here.

Signed-off-by: Simon McVittie smcv@debian.org