Revert "Another little stepping optimization: if any of the source step...

Revert "Another little stepping optimization: if any of the source step commands are running through a range "

- Revert because this commit introduce several failures in lldb test suite
- http://lab.llvm.org:8011/builders/lldb-x86_64-ubuntu-14.04-cmake/builds/8391
- This reverts commit 78943bb678c2893703ee4e8b41969372740c8a6f.

llvm-svn: 252980