Perf regression since b72

[Charles Oliver Nutter]

I've been fiddling about with performance a bit again recently, and have
noticed a perf degradation since b72. I mentioned this to the Nashorn guys
and Marcus discovered that InlineSmallCode=2000 helped them get back to b72
performance. I can confirm this on JRuby as well, but in any case it seems
that something has regressed.

Here's some numbers with JRuby. Numbers are for b72, hotspot-comp, and
hotspot-comp with InlineSmallCode=2000. You can see that current
hotspot-comp builds do not perform as well as b72 unless that flag is
passed.

https://gist.github.com/headius/de7f99b52847c2436ee4

I have not yet started to explore the inlining or assembly output, but I
wanted to confirm that others are seeing this degradation.

My build of hotspot-comp is current.

I do have some benchmarks that look fine without the additional flag
(neural_net, for example), so I'm confused what's different in the degraded
cases.

- Charlie
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