Update Xen integration test Docker image

Ubuntu 16.04 does not have a sufficiently recent compiler to build CBMC.
Use a more modern release and update packages as needed.

Fixes: #8193

Author: tautschnig

integration/xen/Dockerfile

@@ -1,9 +1,9 @@
-FROM ubuntu:16.04
+FROM ubuntu:22.04
 
 RUN apt-get update && apt-get --no-install-recommends -y install \
         build-essential gcc git make flex bison \
-        software-properties-common curl python \
-        bin86 gdb bcc liblzma-dev python-dev gettext iasl \
+        software-properties-common curl python3 \
+        bin86 gdb bcc liblzma-dev python3-dev gettext iasl \
         uuid-dev libncurses5-dev libncursesw5-dev pkg-config \
         libgtk2.0-dev libyajl-dev sudo time