As a follow-up to JDK-8086045, analysis has found a number of small, simple improvements that can be made to further improve startup characteristics of java.lang.invoke.CallSite and MethodType:

- CallSite::<clinit> looks up two MethodHandles that aren't used in many typical applications
- CallSite.CONTEXT_OFFSET calculated but never used
- The ConcurrentHashMap in MethodType$ConcurrentWeakInternSet is resized multiple times even for relatively trivial tests, and initializing it to a larger size is footprint neutral but beneficial to startup for most users

This small set of non-intrusive changes has a measurable impact to startup, which partially help with a number of startup regressions seen in 9.