Limit maximum number of open file descriptors to overcome titan bug

Without this, titan tries to allocate too much memory and triggers OOM
under some systems (happening here with 16GB of RAM).

Related: https://gitlab.eclipse.org/eclipse/titan/titan.core/-/issues/690
Change-Id: Iafa8cfa769386e63e1d879d8cce6e24b244d9a6f

start-testsuite.sh

@@ -45,6 +45,10 @@ fi
 #TITAN_LIBRARY_PATH="$TTCN3_DIR/lib"
 #TTCN3_BIN_DIR="$TTCN3_DIR/bin"
 
+# Limit max num of open file descriptors to workaround titan.core bug:
+# https://gitlab.eclipse.org/eclipse/titan/titan.core/-/issues/690
+ulimit -n 100000
+
 # below is for the debian packages
 TTCN3_BIN_DIR="${TTCN3_BIN_DIR:-/usr/bin}"
 TITAN_LIBRARY_PATH="${TITAN_LIBRARY_PATH:-/usr/lib/titan:/usr/ttcn3/lib}"