This makes meson actually parse the individual test
results. Most of the time, it does not make a difference,
but one case where it does is when all the individual
tests of a binary are skipped, meson will mark the
test as skipped.
This adds a GDK_DEBUG=default-settings flag which disables reads
from xsettings and Xft resources, and enables this for the testsuite.
This is one less way to get different testresults depending on the
environment. In particular, it was failing the css tests for me
due to getting the wrong font size because i have a different dpi.
