I found a test began failing after 0d35995 (cc @subbuss)
Repro:
% git clone [email protected]:sparklemotion/http-cookie.git
% cd http-cookie
% jruby -Ilib test/test_http_cookie_jar.rb # => fail
% jruby --dev -Ilib test/test_http_cookie_jar.rb # => OK
With 8a04861 it passes so I guess 0d35995 is a cause but I don't have enough knowledge of IR optimization.