[MINOR] Cleanup bivariate stats algorithm script (list, ifelse, format)
[MINOR] Cleanup bivariate stats algorithm script (list, ifelse, format)

This patch makes a couple of minor cleanups of the bivariate statistics
algorithm in order to use the new as.matrix(list) in practice. This
significantly reduces the script size. Furthermore, we also use the new
ifelse and fix the messy formatting.

deroneriksson/incubator-systemml,niketanpansare/systemml,gweidner/systemml,gweidner/incubator-systemml,apache/incubator-systemml,gweidner/incubator-systemml,gweidner/incubator-systemml,deroneriksson/incubator-systemml,niketanpansare/incubator-systemml,apache/incubator-systemml,deroneriksson/incubator-systemml,apache/incubator-systemml,deroneriksson/systemml,gweidner/incubator-systemml,gweidner/incubator-systemml,deroneriksson/incubator-systemml,niketanpansare/incubator-systemml,niketanpansare/systemml,apache/incubator-systemml,niketanpansare/systemml,apache/incubator-systemml,gweidner/incubator-systemml,niketanpansare/incubator-systemml,deroneriksson/incubator-systemml,niketanpansare/systemml,deroneriksson/incubator-systemml,niketanpansare/systemml,niketanpansare/incubator-systemml,deroneriksson/systemml,gweidner/systemml,deroneriksson/systemml,deroneriksson/systemml,apache/incubator-systemml,gweidner/systemml,gweidner/systemml,niketanpansare/systemml,deroneriksson/systemml,deroneriksson/systemml,gweidner/systemml,gweidner/systemml