Add Reflect.initValue(Class)

[lukaseder]

Sometimes, it's necessary to get an initialisation value for a given Class reference, i.e. the value that would be present as a default initialisation value after object construction:

class X {
  i int;
}

assertEquals(0, new X().i);

There doesn't seem to be a JDK method to do this. Guava has a method, though:
https://stackoverflow.com/q/52988458/521799