Use tonistiigi/binfmt instead of our multi-arch register.sh

Looking deeper into the logs there are a lot of errors like:
`script exited with error 1`

Initial reaction was that there was a problem with download, but it
looks like the script we use to register the qemu emulators may be at
fault, let's try this alternate mechanism.

Signed-off-by: Davanum Srinivas <davanum@gmail.com>

test/images/agnhost/Dockerfile

@@ -27,8 +27,7 @@ CROSS_BUILD_COPY qemu-QEMUARCH-static /usr/bin/
 # - iproute2: includes ss used in NodePort tests
 # from iperf image
 # install necessary packages: iperf, bash
-RUN retry () { i=0; while [ $i -lt 9 ]; do "$@" && return || sleep 30; i="${i+1}"; done; "$@"; } \
-  && retry apk --update add bind-tools curl netcat-openbsd iproute2 iperf bash && rm -rf /var/cache/apk/* \
+RUN apk --update add bind-tools curl netcat-openbsd iproute2 iperf bash && rm -rf /var/cache/apk/* \
   && ln -s /usr/bin/iperf /usr/local/bin/iperf \
   && ls -altrh /usr/local/bin/iperf
 

test/images/image-util.sh

@@ -165,7 +165,7 @@ build() {
             if [[ $(id -u) -ne 0 ]]; then
 	            sudo="sudo"
             fi
-            ${sudo} "${KUBE_ROOT}/third_party/multiarch/qemu-user-static/register/register.sh" --reset -p yes
+            ${sudo} docker run --rm --privileged tonistiigi/binfmt:latest --install all
             curl -sSL https://github.com/multiarch/qemu-user-static/releases/download/"${QEMUVERSION}"/x86_64_qemu-"${QEMUARCHS[$arch]}"-static.tar.gz | tar -xz -C "${temp_dir}"
             # Ensure we don't get surprised by umask settings
             chmod 0755 "${temp_dir}/qemu-${QEMUARCHS[$arch]}-static"