tests: Don’t spawn test processes via the terminal in the appinfo test

There seems to be no reason to do so, and since the `appinfo` test was
ported to use `G_TEST_OPTION_ISOLATE_DIRS`, it has been causing
coredumps to accumulate. `gnome-terminal` was chosen as the terminal,
but it couldn’t find its GSettings schemas due to all the XDG
environment variables being cleared to `/dev/null` by
`G_TEST_OPTION_ISOLATE_DIRS`.

In order to keep using `gnome-terminal` as a subprocess in the tests,
we’d need to explicitly set up its environment so it can load the right
GSettings schemas. That’s a lot of work for not much gain.

Signed-off-by: Philip Withnall <withnall@endlessm.com>

Helps: #436

gio/tests/appinfo-test.desktop.in

@@ -9,7 +9,7 @@ Comment=GAppInfo example
 Comment[de]=GAppInfo Beispiel
 Exec=@installed_tests_dir@/appinfo-test --option %U %i --name %c --filename %k %m %%
 Icon=testicon.svg
-Terminal=true
+Terminal=false
 StartupNotify=true
 StartupWMClass=appinfo-class
 MimeType=image/png;image/jpeg;

gio/tests/appinfo.c

@@ -87,7 +87,7 @@ test_launch_no_app_id (void)
     "Comment=GAppInfo example\n"
     "Comment[de]=GAppInfo Beispiel\n"
     "Icon=testicon.svg\n"
-    "Terminal=true\n"
+    "Terminal=false\n"
     "StartupNotify=true\n"
     "StartupWMClass=appinfo-class\n"
     "MimeType=image/png;image/jpeg;\n"