Weston IVI test fails without install

At least ivi-layout test fails due to a bad config:

/home/pq/local/share/weston/background.png: No such file or directory
Failed to load_cairo_surface /home/pq/local/share/weston/background.png

...

weston: ../../git/weston/ivi-shell/hmi-controller.c:916: ivi_hmi_controller_set_background: Assertion `ivisurf != NULL' failed.
ivi-layout-test-client: ../../git/weston/tests/weston-test-client-helper.c:931: create_client: Assertion `wl_display_roundtrip((client)->wl_display) >= 0' failed.

The file does not exist yet, because I have not done 'ninja install'.

To reproduce, make sure your install prefix is clean of any Weston files, and run ninja test.

This seems to be specific to the Meson build.