Further reduction of failing test case.
Trim unused code.
'exit' -> 'return' in instrumentation fn name.
Trivial: make whitespace output nicer.
Trivial: whitespace fixes.
Fix logical error in operator==(FunctionEvent x2).

E1.direction() is *always* equal to E1.direction(), etc. What we actually want to check is E1 vs E2.

This fixes tesla/test/Regression/missing-exit-instr.ll.