Utilities/js: Make it possible to exit via two consecutive ^C's

Apparently this is common in the js repl world.
Fixes #743.

Userland/Libraries/LibLine/KeyCallbackMachine.cpp

@@ -7,10 +7,6 @@
 #include <AK/Debug.h>
 #include <LibLine/Editor.h>
 
-namespace {
-constexpr u32 ctrl(char c) { return c & 0x3f; }
-}
-
 namespace Line {
 
 void KeyCallbackMachine::register_key_input_callback(Vector<Key> keys, Function<bool(Editor&)> callback)