Cleaned up and fixed tests:
Cleaned up and fixed tests:

Some things were repeated. One thing we didn't test is whether
each type passes the "is_" alternative. That is, will a hashref
pass is the "is_hashref", not just "is_plain_hashref" or
"is_blessed_hashref". This is now added.

There is also room for "is_any" at any such point.

I've also consolidated the "is_ref" tests.

p5pclub/ref-util