test/meson.build: Add missing tests

These are entries that are present in test/Makefile.sources, but are
missing from test/meson.build.

Signed-off-by: Uli Schlachter <psychon@znc.in>
5 jobs for small-build-system-fixes in 23 minutes and 42 seconds (queued for 1 second)
Status Job ID Name Coverage
  Prep
passed #6701782
fedora image

00:00:31

 
  Test
passed #6701783
fedora autotools build

00:23:10

passed #6701784
fedora meson build

00:00:26

passed #6701785
docker windows 1809
meson vs2017 amd64

00:02:57

passed #6701786
docker windows 1809
meson vs2017 x86

00:02:59