test_beginendblock.rb: avoid leaking threads
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@46242 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
test_beginendblock.rb: avoid leaking threads
kill, but also wait the end.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@46242 b2dd03c8-39d4-4d8f-98ff-823fe69b080e