Make -f semantics match those of the C engine.

js/rhino/org/mozilla/javascript/tools/shell/Main.java

@@ -186,6 +186,7 @@ public class Main {
                 continue;
             }
             if (arg.equals("-f")) {
+                global.processStdin = false;
                 if (++i == args.length)
                     usage(arg);
                 if (args[i].equals("-"))

js/rhino/toolsrc/org/mozilla/javascript/tools/shell/Main.java

@@ -186,6 +186,7 @@ public class Main {
                 continue;
             }
             if (arg.equals("-f")) {
+                global.processStdin = false;
                 if (++i == args.length)
                     usage(arg);
                 if (args[i].equals("-"))