gh-112088: Run autoreconf in GHA check_generated_files (#112090)

The "Check if generated files are up to date" job of GitHub Actions
now runs the "autoreconf -ivf -Werror" command instead of the "make
regen-configure" command to avoid depending on the external quay.io
server.

Add Tools/build/regen-configure.sh script to regenerate the configure
with an Ubuntu container image. The
"quay.io/tiran/cpython_autoconf:271" container image
(https://github.com/tiran/cpython_autoconf) is no longer used.

Tools/build/regen-configure.sh

@@ -0,0 +1,31 @@
+#!/usr/bin/env bash
+
+set -e -x
+
+# The check_generated_files job of .github/workflows/build.yml must kept in
+# sync with this script. Use the same container image than the job so the job
+# doesn't need to run autoreconf in a container.
+IMAGE="ubuntu:22.04"
+DEPENDENCIES="autotools-dev autoconf autoconf-archive pkg-config"
+AUTORECONF="autoreconf -ivf -Werror"
+
+WORK_DIR="/src"
+SHELL_CMD="apt-get update && apt-get -yq install $DEPENDENCIES && cd $WORK_DIR && $AUTORECONF"
+
+abs_srcdir=$(cd $(dirname $0)/../..; pwd)
+
+if podman --version &>/dev/null; then
+    RUNTIME="podman"
+elif docker --version &>/dev/null; then
+    RUNTIME="docker"
+else
+    echo "$@ needs either Podman or Docker container runtime." >&2
+    exit 1
+fi
+
+PATH_OPT=""
+if command -v selinuxenabled >/dev/null && selinuxenabled; then
+    PATH_OPT=":Z"
+fi
+
+"$RUNTIME" run --rm -v "$abs_srcdir:$WORK_DIR$PATH_OPT" "$IMAGE" /usr/bin/bash -c "$SHELL_CMD"