DebugInfo: regenerate test case from Clang to adjust for fixes/improvements

I hit some problems with future work due to the member subprogram of
'a_b's type having a subprogram (an implicit default ctor, !52 in the
pre-commit source) with no name. Clang now generates a name for such a
function but in this case doesn't even emit debug info for it as it is
unused (Clang never emits the body of the ctor, instead just emitting
memset if needed).