Remove unnecessary timeout

if timeout is given, breaking condition is set. if breaking condition
is positive, the it passed and without errors. So no need to timeout.

https://github.com/fluent/fluentd/blob/a8b6d6ff4aa83bb0f7c8aa54f3367018383236d6/lib/fluent/test/driver/base.rb#L81
https://github.com/fluent/fluentd/blob/a8b6d6ff4aa83bb0f7c8aa54f3367018383236d6/lib/fluent/test/driver/base.rb#L215

Signed-off-by: Yuta Iwama <ganmacs@gmail.com>

test/plugin/test_in_tail.rb

@@ -1073,7 +1073,7 @@ def test_unwatched_files_should_be_removed
                               })
       d = create_driver(config, false)
       d.end_if { d.instance.instance_variable_get(:@tails).keys.size >= 1 }
-      d.run(expect_emits: 1, shutdown: false, timeout: 1) do
+      d.run(expect_emits: 1, shutdown: false) do
         File.open("#{TMP_DIR}/tail.txt", "ab") { |f| f.puts "test3\n" }
       end