Relax timeout limit for FreeBSD

* http://rubyci.s3.amazonaws.com/freebsd12/ruby-master/log/20230322T063002Z.fail.html.gz
  * http://rubyci.s3.amazonaws.com/freebsd13/ruby-master/log/20230322T063002Z.fail.html.gz

test/ruby/test_process.rb

@@ -1526,7 +1526,7 @@ class TestProcess < Test::Unit::TestCase
   def test_wait_exception
     bug11340 = '[ruby-dev:49176] [Bug #11340]'
     t0 = t1 = nil
-    sec = 3
+    sec = RUBY_PLATFORM =~ /freebsd/ ? 6 : 3
     code = "puts;STDOUT.flush;Thread.start{gets;exit};sleep(#{sec})"
     IO.popen([RUBY, '-e', code], 'r+') do |f|
       pid = f.pid