Question: Are there any world-wide known Music Certification tests that you can take to use in your resume: for example, to demonstrate basic musical abilities?

I used to work in IT, where it is very common for companies like Oracle and Zend to arrange that kind of certification for a programming language or framework.

Answer: 
Music is such a big field that it isn't really possible to answer this.

There are organisations and colleges such as Berklee which have some international reputation, it can be helpful to have something from them.

But in many areas, the qualification is simply showing you can do what is needed. For instance, as a jazz musician you are likely to pick up work by showing you can play your \*\*\*\* off without actually being an \*\*\*\*.

Music is a field that is extremely results driven. Pieces of paper don't really make much difference when you are on stage. Being able to be there on time, looking the part, and playing well are the main thing. Even people who do study at conservatory will often acknowledge that the main benefit was contacts they made, rather than the actual qualification.
Generally speaking, just about every country will have music exam boards, a lot of them world wide, like ABRSM. Most have been established for many years, and the standard at any particular grade should be just that - standard.

So, on a c.v., stating Grade VI clarinet ABRSM, Trinity, LCM, AMEB etc., should give a good clue to someone reading that c.v., possibly with a little homework.

Worth a look at IMEB - which it seems is the International Music Examination Board, and, as such, would have responsibility to align all boards.