[bin] Do not restrict alpha-beta-CROWN to a single thread.

bin/abcrown.sh

@@ -25,5 +25,5 @@ if [ "$1" = "--version" ]; then
     SCRIPT_DIR=$( dirname -- "$0"; )
     $SCRIPT_DIR/dummyversion.py "abcrown"
 else
-    OMP_NUM_THREADS=1 python3 -m abcrown "$@"
+    python3 -m abcrown "$@"
 fi