Test refactoring: move shortest path weights to a namespace instead of class

This will allow accessing them unqualified if you include a 'using namespace'. The downside is that it ceases to really be a fixture; now they are just global variables.
TraceSplitSemElem: Fix for a bunch of compiler errors
Tests for TraceSplitSemElem: Add fixtrue to generate maps; quick validation test
REORDER AND SQUASH WITH TWO BACK Fix for a TraceSplitSemElem compile error
REORDER AND SQUASH: this file needed to be committed a couple ago, with the last test refactoring commit
Tests for TraceSplitSemElem: add a couple tests