Use JDK Equals in UTF8

Starting in JDK9, the JDK provides a vectorized ways to test if two specified arrays of bytes, over the specified ranges, are equal to one another. This uses some nice vectorization and in-line methods under the covers.

https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/util/Arrays.html#equals(byte%5B%5D,int,int,byte%5B%5D,int,int)

Use this when determining if two UTF8 Strings are equal.