Fix a debug-types-section bug in debug-parser-dwarf
Summary:
With `-fdebug-types-section` enabled, a struct definition may simply
be a reference to a definition in a different type-unit. If we happen
to pick one of those as the canonical definition, it fails because it
looks like an definition (no declaration attribute), but is missing a
size attribute.
Just follow the reference if we find one.
Reviewed By: alexeyt
Differential Revision:
D15251592
fbshipit-source-id:
b1a2edfcd6625a750f0382f85ce410625960d5b6