[ Reason ]
Fix two flaky tests.

[ Impact ]
Package may FTBFS.

[ Tests ]
I've checked that the package builds ok on the systems where it used to fail.

[ Risks ]
Very low. We are disabling a test in a _test file, and increasing a timeout value in a non _test file
in code which is otherwise only used by tests.

[ Checklist ]
   [X] *all* changes are documented in the d/changelog
   [X] I reviewed all changes and I approve them
   [X] attach debdiff against the package in (old)stable
   [X] the issue is verified as fixed in unstable

[ Changes ]
One flaky test has been disabled.
The other test has an increased timeout.

[ Other info ]
I will upload the package next.

Sorry. Actually, this explanation is not correct.

The problem was that one test required at least two workers, but it
was taking the number of CPUs to decide about the number of workers,
so this failed on single-cpu systems. The change is trivial anyway
and I've verified that it fixes the build failire.

Thanks.