[TravisCI] If unit tests fail to execute stop testing.
[TravisCI] If unit tests fail to execute stop testing.

travitch/whole-program-llvm,travitch/whole-program-llvm,travitch/whole-program-llvm,SRI-CSL/whole-program-llvm,SRI-CSL/whole-program-llvm,SRI-CSL/whole-program-llvm,SRI-CSL/whole-program-llvm,SRI-CSL/whole-program-llvm,travitch/whole-program-llvm