testsuite: Remove serialize-deserialize test

The serialize-deserialize test is completely handled via the new
nodeparser tests.

So move those tests over and delete the old test binary.
5 jobs for wip/otte/for-master in 22 minutes and 57 seconds (queued for 7 seconds)
Status Job ID Name Coverage
  Build
passed #304705
fedora-x86_64

00:03:26

passed #304706
win32
msys2-mingw32

00:22:56

 
  Flatpak
manual #304707
allowed to fail manual
flatpak-manual:demo
manual #304709
allowed to fail manual
flatpak-manual:icon-browser
manual #304708
allowed to fail manual
flatpak-manual:widget-factory