Closes GH-10074

The avaraging tests seems to be flaky due to rounding errors. Test fails on
x86 and s390x

https://github.com/ImageMagick/ImageMagick/issues/1576#issuecomment-494595404

fixes #9555

This was unintentionally pushed to wrong branch.

This reverts commit 4ebe0d10.

fixes #9742

openmp appears to cause problems on some machines. We disable it
everywhere.

fixes #9190

we pull in x11 libraries anyways due to librsvg and pango so it does not
make any sense to not build the reset with libx11.

the test still seems to deadlock on s390x when openmp is enabled.
Disable it again.

We also disbale running the tests as fakeroot because it is not necessary.

https://www.imagemagick.org/script/index.php:

> It is distributed under the Apache 2.0 license.

The LICENSE file contains a preface, but that just explains the
following text of Apache-2.0 license in simple terms.

the test seems to deadlock if openmp is enabled

fix the abiver