[debuginfo-tests][Dexter] Fix some Windows-unfriendly Dexter behaviours

Authored by jmorse on Feb 13 2020, 6:24 AM.


[debuginfo-tests][Dexter] Fix some Windows-unfriendly Dexter behaviours

These are some minor things that I've run into on Windows, largely in
error handling paths:

  • Giving --lldb-executable on Windows triggers a "useless option" code path, which touches an attribute that only exists in the list_debuggers tool. Switch this to use hasattr, which will work in all subtools.
  • We were over-decoding some text reporting errors, but only in an exception path
  • The path to lldb on Windows needs to be quoted (even though dexter isn't making use of it).

Differential Revision: https://reviews.llvm.org/D74546