StringCoding.hasNegatives

[Brett Okken]

> The current pure Java implementation does two things: it provides a fallback
> for pure-interpreter JVMs and it provides the reader with a simple implementation.
> I'm not at all sure we'd want a complex implementation.

I thought this might be the case.

> Having said that, if I were looking at a faster pure Java version of
> this logic, I'd look at MethodHandles.byteArrayViewVarHandle().

I considered that, but had 2 concerns:
1. creating potential dependency/initialization order issues
2. creating/managing a constant VarHandle that would never be used
with normal compiler behavior

Overall it sounds like this is not worthwhile. Thanks for taking a look.

Brett