Tweak inlining heuristics.

go/lem driven:

Performance:
Richards +41%
CaffeineMethod +43%
ReversiBench: +52%
Towers: +73%
Tak: +85%

Memory use: 7% less memory
CompileTime: 14% increase
CodeSize: 8% increase

Last three measures are now more acceptable given we JIT.

Change-Id: Ic4aa6535d2b76cf3545ef00e9b2ae32330f10745