tests/docker: add python3-venv dependency

Several debian-based tests need the python3-venv dependency as a
consequence of Debian debundling the "ensurepip" module normally
included with Python.

As mkvenv.py stands as of this commit, Debian requires EITHER:

(A) setuptools and pip, or
(B) ensurepip

mkvenv is a few seconds faster if you have setuptools and pip, so
developers should prefer the first requirement. For the purposes of CI,
the time-save is a wash; it's only a matter of who is responsible for
installing pip and when; the timing is about the same.

Arbitrarily, I chose adding ensurepip to the test configuration because
it is normally part of the Python stdlib, and always having it allows us
a more consistent cross-platform environment.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20230511035435.734312-12-jsnow@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

tests/docker/dockerfiles/debian-all-test-cross.docker

@@ -57,7 +57,8 @@ RUN DEBIAN_FRONTEND=noninteractive eatmydata \
         gcc-sh4-linux-gnu \
         libc6-dev-sh4-cross \
         gcc-sparc64-linux-gnu \
-        libc6-dev-sparc64-cross
+        libc6-dev-sparc64-cross \
+        python3-venv
 
 ENV QEMU_CONFIGURE_OPTS --disable-system --disable-docs --disable-tools
 ENV DEF_TARGET_LIST aarch64-linux-user,alpha-linux-user,arm-linux-user,hppa-linux-user,i386-linux-user,m68k-linux-user,mips-linux-user,mips64-linux-user,mips64el-linux-user,mipsel-linux-user,ppc-linux-user,ppc64-linux-user,ppc64le-linux-user,riscv64-linux-user,s390x-linux-user,sh4-linux-user,sparc64-linux-user

tests/docker/dockerfiles/debian-hexagon-cross.docker

@@ -20,7 +20,8 @@ RUN apt-get update && \
         bison \
         flex \
         git \
-        ninja-build && \
+        ninja-build \
+        python3-venv && \
 # Install QEMU build deps for use in CI
     DEBIAN_FRONTEND=noninteractive eatmydata \
     apt build-dep -yy --arch-only qemu

tests/docker/dockerfiles/debian-riscv64-cross.docker

@@ -28,7 +28,8 @@ RUN DEBIAN_FRONTEND=noninteractive eatmydata apt install -yy \
     libglib2.0-dev \
     ninja-build \
     pkg-config \
-    python3
+    python3 \
+    python3-venv
 
 # Add ports and riscv64 architecture
 RUN echo "deb http://ftp.ports.debian.org/debian-ports/ sid main" >> /etc/apt/sources.list

tests/docker/dockerfiles/debian-tricore-cross.docker

@@ -33,7 +33,8 @@ RUN apt update && \
        pkgconf \
        python3-pip \
        python3-setuptools \
-       python3-wheel
+       python3-wheel \
+       python3-venv
 
 RUN curl -#SL https://github.com/bkoppelmann/package_940/releases/download/tricore-toolchain-9.40/tricore-toolchain-9.4.0.tar.gz \
     | tar -xzC /usr/local/