gtester: fix test result in gtester XML report

This was accidentally broken with the changes done for
https://bugzilla.gnome.org/show_bug.cgi?id=790934
4 jobs for 1305-gtester-sense in 19 minutes and 23 seconds (queued for 24 seconds)
Status Job ID Name Coverage
  Build
passed #37817
fedora-meson-x86_64

00:05:40

passed #37818
win32
msys2-mingw32

00:06:29

passed #37819
win32
vs2017-x64

00:06:01

 
  Coverage
passed #37820
coverage

00:01:12

76.6%