Removed the expectedFailure decorator from test_with_dwarf_and_run_command() test case

as it now passes.  Added some extra tests to breakpoint_creation_by_filespec_python().

More clarification for the "os command" output and error as defined in
lldbtest.system() function.

Cleaned up the option processing of the test driver (dotest.py) and fixed the comment
about enabling gdb-remote logging.  Example:

$ GDB_REMOTE_LOG=/tmp/log.txt ./dotest.py -v -t enum_types

llvm-svn: 113868