[ruby/io-console] Fix timeout type error (#18)

Fixed TypeError when IO#getch timed out

`rb_io_wait` returns a bit-flags Integer representing available
events, or Qfalse if timed out.  Also the result of `NUM2INT` is
not a `VALUE`.

```
$ ./bin/ruby -v -rio/console -e "p IO.console.getch(intr: true, time: 0.1)"
ruby 3.0.0dev (2020-10-09T20:27:30Z master 5ea2ea74cc) [x64-mingw32]
-e:1:in `getch': no implicit conversion of false into Integer (TypeError)
        from -e:1:in `<main>'
```

https://github.com/ruby/io-console/commit/3bdfaf62df

1 files changed, 4 insertions, 0 deletions

diff --git a/test/io/console/test_io_console.rb b/test/io/console/test_io_console.rb
index 3613a2ce32..3962de3790 100644
--- a/test/io/console/test_io_console.rb
+++ b/test/io/console/test_io_console.rb
@@ -471,6 +471,10 @@ defined?(IO.console) and TestIO_Console.class_eval do
     ensure
       IO.console(:close)
     end
+
+    def test_getch_timeout
+      assert_nil(IO.console.getch(intr: true, time: 0.1, min: 0))
+    end
   end
 end