gdk-pixbuf: do not use tools from gdk-pixbuf-native when building tests

The patch that allows to do so has not been accepted upstream, and wasn't correctly
working as it was running a native executable (gdk-pixbuf-query-loaders) with target .so plugins.

On the other hand, out of 20+ (currently 23) tests only three require
running binaries at build time to produce special test-specific input data:

cve-2015-4491
pixbuf-pixdata
pixbuf-resource

So let's simply omit these from the build: this can be done with a far
less invasive patch which has a chance of being accepted upstream.

gdk-pixbuf-print-mime-types is no longer installed
(the replaced patch was doing that).

Signed-off-by: Alexander Kanavin <alex@linutronix.de>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
(cherry picked from commit 0d926508)
Signed-off-by: Steve Sakoman <steve@sakoman.com>