RFR: 8174222: LambdaMetafactory: validate inputs and improve documentation

[Dan Smith]

Sorry, intended for core-libs-dev. Please disregard.

> On Mar 20, 2019, at 6:18 PM, Dan Smith <daniel.smith at oracle.com> wrote:
> 
> http://cr.openjdk.java.net/~dlsmith/8174222/webrev.00/ <http://cr.openjdk.java.net/~dlsmith/8174222/webrev.00/>
> 
> Please review this update to java.lang.invoke.LambdaMetafactory. Adds some argument validation with tests; improves documentation; renames some variables.
> 
> JBS: https://bugs.openjdk.java.net/browse/JDK-8174222 <https://bugs.openjdk.java.net/browse/JDK-8174222>
> 
> —Dan
>