[CDASH] add option to set end time for ctest tests + slurm script for it

Finally found the right way to provide the stop time: without date and without timezone

My local test on cbmfles01 and vae23 with Experimental builds seem to work and stop as expected, we will probably have to wait the first runs to see how helpful the CDASH report is when the timeout is triggered.
It seems that the devs are still working on this: CMAKE issue 25146: CTest: incomplete report when stop-time is reached
But that should still be better than the current "no report at all", at least to identify areas of improvement on our test durations.

scripts/find_slurm_ctest_stop_time.sh

+#!/bin/bash
+# Copyright (C) 2024 GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt
+# SPDX-License-Identifier: GPL-3.0-only
+# First commited by Pierre-Alain Loizeau
+
+# Script used to compute a "safe" end time for the ctest test stage of a Dart/Cdash chain in order
+# to have enough time to upload the CDASH results before a job is killed on a SLURM cluster (e.g. Virgo @ GSI)
+#
+# Usage:
+# - with a full/relative/absolute path to an output Dart.cfg file as parameter, where the export will be added
+# - without any parameter, then setting an export
+#
+# => Typical use case would be calling it in your sbatch script after setting up the other parts of the
+#    Dart.cfg gile and before the call to Dart.sh
+#>> echo "export NCPU=10" >> ${DART_CFG}
+#>> [...]
+#>> ./scripts/find_slurm_ctest_stop_time.sh ${DART_CFG}
+#>> [...]
+#>> ./Dart.sh Weekly ./${DART_CFG} &> ${OUT_DIR}/Dart_weekly.log
+
+# SLURM end time
+END_TIME=`squeue -j ${SLURM_JOB_ID} -h --Format EndTime`
+echo "SLURM Job end time ${END_TIME}"
+
+# Ctest end time = SLURM -5 minutes (should be enough for coverage and uploads)
+# => Not working as ctest expects the "time point in hours-minutes-seconds within current day"
+#                         + hardcode the day/year/month to the current day...
+# https://gitlab.kitware.com/cmake/cmake/-/blob/master/Help/manual/ctest.1.rst#L440
+# https://gitlab.kitware.com/cmake/cmake/-/blob/master/Source/cmCTest.cxx#L1991
+# https://gitlab.kitware.com/cmake/cmake/-/blob/master/Source/cmCTest.cxx#L3012
+# https://gitlab.kitware.com/cmake/cmake/-/blob/master/Source/CTest/cmCTestRunTest.cxx#L811
+# => Does not work for long running tests close to end of the day
+# CTEST_END_TIME_LIMIT=`date -d "${END_TIME}CET -5minutes" +"%Y-%m-%d %H:%M:%S %z"`
+# => But following should be ok for weeklies starting early in the morning
+# => Does not work at least with cmake 3.22 and 3.24, seesm that timezone is breaking decoding
+#    (tried all timezone options of date, with and without space between time and timezone)
+#CTEST_END_TIME_LIMIT=`date -d "${END_TIME}CET -5minutes" +"%H:%M:%S %z"`
+# => Working! but probably unsafe on day of Summer time swaps + if tests run close to midnight...
+CTEST_END_TIME_LIMIT=`date -d "${END_TIME}CET -5minutes" +"%H:%M:%S"`
+echo "Setting the job time limit for ctest to ${CTEST_END_TIME_LIMIT} to make sure CDASH data is uploaded"
+
+if [[ $# -eq 1 ]]; then
+  # Set the export in the chosen Dart.cfg file
+  echo "export CTEST_END_TIME_LIMIT=\"${CTEST_END_TIME_LIMIT}\"" >> $1
+else
+  export CTEST_END_TIME_LIMIT=\"${CTEST_END_TIME_LIMIT}\"
+fi