Hi Ger,
absolutely yes! You can drop that table safely.
It's created by the built-in tests present in the XMLDB Editor, so its presence just means that you've executed them in the past.
In fact, you can find up to 3 tables:
* testtable
* anothertest
* newnameforthetable
It seems that we (my fault!) forgot to drop them at the end of the test. I'll fix that ASAP, until then, as said, it's 100% safe to drop them manually.
Ciao
Edited/PS: This issue has been tracked as
MDL-20571.