Remove Commons Collections Test Framework

[melloware]

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Commons Collection Test Framework is... a) no longer supported b) has not been built since 2013 c) does NOT even have a POM in Maven Central its just a JAR.

So BeanUtils2 should not be depending on it. This PR removes that dependency and brings in the code necessary for the unit tests.

[sebbASF]

It would be helpful to add a comment to the copied files pointing to the source of the copy. Now that we are using independent Git repos, it's not possible to track copies across Commons components.

[melloware]

Added to each class header:

 * <p>
 * Copied from Commons Collection 4.
 * @see <a href="https://github.com/apache/commons-collections">Commons Collections 4</a>

[sebbASF]

Thanks, but it would be better to link to the actual files please

[melloware]

Good idea all links updated to point to their original file in GitHub.

[garydgregory]

I'll try and take a look this week...