tests/docker: Use Fedora containers for MinGW cross-builds in the gitlab-CI

tests/docker: Use Fedora containers for MinGW cross-builds in the gitlab-CI

According to our support policy, we do not support Debian 9 in QEMU
anymore, and we only support building the Windows binaries with a
very recent version of the MinGW toolchain. So we should not test
the MinGW cross-compilation with Debian 9 anymore, but switch to
something newer like Fedora. To do this, we need a separate Fedora
container for each build that provides the QEMU_CONFIGURE_OPTS
environment variable.
Unfortunately, the MinGW 64-bit compiler seems to be a little bit
slow, so we also have to disable some features like "capstone" in the
build here to make sure that the CI pipelines still finish within a
reasonable amount of time.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20200921174320.46062-2-thuth@redhat.com>
Message-Id: <20200925154027.12672-10-alex.bennee@linaro.org>