common: factor out common opts to all scripts

gem5-shell

@@ -1,16 +1,10 @@
 #!/usr/bin/env bash
 . "$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)/common"
 common_gem5=true
-while getopts M:n: OPT; do
+while getopts "${common_getopts_flags}" OPT; do
   case "$OPT" in
-    M)
-      common_gem5_variant="$OPTARG"
-      ;;
-    n)
-      common_run_id="$OPTARG"
-      ;;
     ?)
-      exit 2
+      common_getopts_case "$OPT"
       ;;
   esac
 done