Add EX perf testing script (chapel-lang#25375)

We would like to gather nightly performance results for an HPE Cray EX
machine. This PR adds a script to set things up for such a job.

[Reviewed by @jhh67]

util/cron/test-perf.hpe-cray-ex.ofi.bash

@@ -0,0 +1,23 @@
+#!/usr/bin/env bash
+#
+# Run performance tests on an HPE Cray EX
+
+CWD=$(cd $(dirname $0) ; pwd)
+
+source $CWD/common.bash
+source $CWD/common-ofi.bash || \
+  ( echo "Could not set up comm=ofi testing." && exit 1 )
+source $CWD/common-hpe-cray-ex.bash
+
+export CHPL_RT_COMM_OFI_EXPECTED_PROVIDER="cxi"
+export CHPL_RT_MAX_HEAP_SIZE=16g
+
+export CHPL_TEST_PERF_SUBDIR="hpe-cray-ex"
+export CHPL_TEST_PERF_CONFIG_NAME='16-node-hpe-cray-ex'
+export CHPL_NIGHTLY_TEST_CONFIG_NAME="perf.hpe-cray-ex.ofi"
+
+nightly_args="${nightly_args} -no-buildcheck"
+perf_args="-numtrials 1"
+perf_hpe_cray_ex_args="-startdate 06/25/24"
+
+$CWD/nightly -cron ${perf_args} ${perf_hpe_cray_ex_args} ${nightly_args}