run: support multiple simultaneous runs and run output directories

gem5-shell

@@ -1,4 +1,15 @@
 #!/usr/bin/env bash
-offset="${1:-0}"
-base=3456
-telnet localhost $(($base + $offset))
+. common
+while getopts n: OPT; do
+  case "$OPT" in
+    n)
+      common_run_id="$OPTARG"
+      ;;
+    ?)
+      exit 2
+      ;;
+  esac
+done
+shift "$(($OPTIND - 1))"
+set_common_vars -n "$common_run_id" "$arch" true
+telnet localhost "$common_gem5_telnet_port"