Remove dockerfile-pgtests (#12336)

scripts-dev/test_postgresql.sh

@@ -1,19 +0,0 @@
-#!/usr/bin/env bash
-
-# This script builds the Docker image to run the PostgreSQL tests, and then runs
-# the tests. It uses a dedicated tox environment so that we don't have to
-# rebuild it each time.
-
-# Command line arguments to this script are forwarded to "tox" and then to "trial".
-
-set -e
-
-# Build, and tag
-docker build docker/ \
-  --build-arg "UID=$(id -u)" \
-  --build-arg "GID=$(id -g)" \
-  -f docker/Dockerfile-pgtests \
-  -t synapsepgtests
-
-# Run, mounting the current directory into /src
-docker run --rm -it -v "$(pwd):/src" -v synapse-pg-test-tox:/tox synapsepgtests "$@"