Add '!nocheck' to build dependencies called 'libtest-*'.

This catches some of the cases where upstream doesn't differentiate between
build_requires and test_requires.
8 jobs for post-buster in 10 minutes and 10 seconds (queued for 1 second)
Status Job ID Name Coverage
  Build
passed #419045
build

00:03:47

 
  Test
passed #419050
autopkgtest

00:06:20

passed #419051
blhc

00:01:17

passed #419049
allowed to fail
lintian

00:01:44

passed #419052
piuparts

00:06:06

passed #419048
reprotest

00:03:51

passed #419047
test-build-all

00:03:54

passed #419046
test-build-any

00:02:20