RFR: 8172905: Minor startup cleanup of CallSite and MethodType

[John Rose]

Using a stable field will consume less meta-space than a nested class, all other things being equal. 

– John

> On Jan 17, 2017, at 5:48 PM, Paul Sandoz <paul.sandoz at oracle.com> wrote:
> 
> It’s either place the static finals in separate nested classes, or use @Stable on non-final statics with lazy initialization in methods (with the possibility of multiple invocations when concurrently executing). Nested classes seems fine here.