Remove StuckServer using backlog and tests relying on it

StuckServer uses kernel implementation details that have changed on
version > 4.4, and causing tests depending on it to fail. Since we can't
find an alternative method to simulate a stuck server without special
permission, and the test itself is not reliable in that they don't fail
on non-stuck servers, remove them from Libcore tests.

Test: CtsLibcoreTestCases
Bug: 32551747
Change-Id: I88d837329d65040a9f8550fff790f8703ea773f3