cpu_time and allocations are 0 when JRuby is used
cpu_time and allocations are 0 when JRuby is used

According to #33449 and #33468, cpu_time and allocations are 0 when
JRuby is used.

```ruby
$ ruby -v
jruby 9.2.1.0-SNAPSHOT (2.5.0) 2018-07-27 13b2df5 Java HotSpot(TM) 64-Bit Server VM 25.181-b13 on 1.8.0_181-b13 [linux-x86_64]
$ bundle exec ruby -w -Itest test/log_subscriber_test.rb -n test_event_attributes
Run options: -n test_event_attributes --seed 6231

F

Failure:
SyncLogSubscriberTest#test_event_attributes [test/log_subscriber_test.rb:84]:
Expected 0 to be > 0.

rails test test/log_subscriber_test.rb:78

Finished in 0.018983s, 52.6791 runs/s, 105.3582 assertions/s.
1 runs, 2 assertions, 1 failures, 0 errors, 0 skips
```

aditya-kapoor/rails,tjschuck/rails,palkan/rails,iainbeeston/rails,esparta/rails,illacceptanything/illacceptanything,yahonda/rails,yalab/rails,utilum/rails,shioyama/rails,georgeclaghorn/rails,rails/rails,kmcphillips/rails,tjschuck/rails,iainbeeston/rails,illacceptanything/illacceptanything,flanger001/rails,notapatch/rails,fabianoleittes/rails,lcreid/rails,mohitnatoo/rails,baerjam/rails,Edouard-chin/rails,schuetzm/rails,palkan/rails,rafaelfranca/omg-rails,printercu/rails,illacceptanything/illacceptanything,MSP-Greg/rails,yhirano55/rails,rails/rails,shioyama/rails,Envek/rails,tgxworld/rails,Erol/rails,gauravtiwari/rails,mohitnatoo/rails,illacceptanything/illacceptanything,illacceptanything/illacceptanything,notapatch/rails,prathamesh-sonpatki/rails,betesh/rails,illacceptanything/illacceptanything,bogdanvlviv/rails,prathamesh-sonpatki/rails,vipulnsward/rails,betesh/rails,kmcphillips/rails,bogdanvlviv/rails,prathamesh-sonpatki/rails,arunagw/rails,jeremy/rails,MSP-Greg/rails,yawboakye/rails,arunagw/rails,repinel/rails,tjschuck/rails,repinel/rails,jeremy/rails,flanger001/rails,Envek/rails,Vasfed/rails,arunagw/rails,yawboakye/rails,betesh/rails,schuetzm/rails,utilum/rails,kddeisz/rails,MSP-Greg/rails,gauravtiwari/rails,bogdanvlviv/rails,rails/rails,joonyou/rails,printercu/rails,eileencodes/rails,Stellenticket/rails,mechanicles/rails,illacceptanything/illacceptanything,mohitnatoo/rails,lcreid/rails,printercu/rails,shioyama/rails,yalab/rails,eileencodes/rails,Envek/rails,EmmaB/rails-1,gauravtiwari/rails,yahonda/rails,mohitnatoo/rails,utilum/rails,fabianoleittes/rails,shioyama/rails,yahonda/rails,MSP-Greg/rails,yawboakye/rails,eileencodes/rails,baerjam/rails,Edouard-chin/rails,baerjam/rails,notapatch/rails,Vasfed/rails,palkan/rails,georgeclaghorn/rails,starknx/rails,Stellenticket/rails,jeremy/rails,georgeclaghorn/rails,notapatch/rails,iainbeeston/rails,vipulnsward/rails,yahonda/rails,EmmaB/rails-1,Vasfed/rails,aditya-kapoor/rails,aditya-kapoor/rails,illacceptanything/illacceptanything,EmmaB/rails-1,tgxworld/rails,aditya-kapoor/rails,prathamesh-sonpatki/rails,Stellenticket/rails,Vasfed/rails,illacceptanything/illacceptanything,Stellenticket/rails,repinel/rails,Erol/rails,eileencodes/rails,illacceptanything/illacceptanything,illacceptanything/illacceptanything,printercu/rails,BlakeWilliams/rails,utilum/rails,tgxworld/rails,yalab/rails,Edouard-chin/rails,flanger001/rails,bogdanvlviv/rails,tjschuck/rails,lcreid/rails,esparta/rails,repinel/rails,illacceptanything/illacceptanything,kmcphillips/rails,joonyou/rails,joonyou/rails,Erol/rails,vipulnsward/rails,joonyou/rails,Envek/rails,yhirano55/rails,BlakeWilliams/rails,rafaelfranca/omg-rails,fabianoleittes/rails,georgeclaghorn/rails,yhirano55/rails,palkan/rails,flanger001/rails,lcreid/rails,rails/rails,mechanicles/rails,tgxworld/rails,iainbeeston/rails,rafaelfranca/omg-rails,starknx/rails,mechanicles/rails,arunagw/rails,kddeisz/rails,BlakeWilliams/rails,kmcphillips/rails,yawboakye/rails,illacceptanything/illacceptanything,kddeisz/rails,illacceptanything/illacceptanything,jeremy/rails,illacceptanything/illacceptanything,BlakeWilliams/rails,esparta/rails,mechanicles/rails,Erol/rails,yhirano55/rails,yalab/rails,Edouard-chin/rails,betesh/rails,schuetzm/rails,esparta/rails,fabianoleittes/rails,schuetzm/rails,baerjam/rails,vipulnsward/rails,starknx/rails,kddeisz/rails