Canonical Frame Address is a DWARF-only concept encoded in the unwind info.
Debugger must store this data for each call frame and provide it to
the eval system based on selected stack frame.
To abstract over format details, we introduce a "Frame Unwind Context".
For DWARF, this context maintains the intermediate unwind state and exposes
the CFA, whereas for PE, it remains empty.
layer functionality for interpreting different types of attributes,
added support for location lists, and API to enable parsing tags with
abstract origin.
Copied the parser from internal repo and integrated with the base layer
(not tested)
Parser uses based/range pattern for which we have an alternative in
string layer (str8_deserial_*)
Nikita Smith
