object.__nonzero__(self) is called to implement truth value testing and the built-in operation bool(),
via a simple delegation to self.IsValid().
Change tests under python_api/lldbutil to utilize this mechanism.
llvm-svn: 131494
o get_parent_frame(frame)
o get_args_as_string(frame)
to lldbutil.py and create TestFrameUtils.py to exercise the utils.
Plus re-arrange the test/python_api/lldbutil to have three directories
for testing iteration, process stack traces, and the just added frame utils.
llvm-svn: 131213