test_io_wait.rb: Increase a timeout for a flaky test

like 68682a5

https://github.com/ruby/ruby/actions/runs/17417763247/job/49449895757?pr=14433

Author: k0kubun

test/io/wait/test_io_wait.rb

@@ -114,7 +114,7 @@ def test_wait_readable_eof
     ret = nil
     assert_nothing_raised(Timeout::Error) do
       q.push(true)
-      t = EnvUtil.apply_timeout_scale(0.1)
+      t = EnvUtil.apply_timeout_scale(1)
       Timeout.timeout(t) { ret = @r.wait_readable }
     end
     assert_equal @r, ret