eja: remove symmetry test that don't work.

I don't know why, but the multiplication table of a commutative
algebra doesn't have to be symmetric. I'll think about this later.
In the meantime, don't crash about it.

Postscript (a month later): left-multiplication and right-multiplication
are the same in the EJA, but not necessarily for the matrices that represent
them. It was wrong to conflate the two concepts in the first place.