[DebugInfo] Don't error for zero-length arange entries

Although the DWARF specification states that .debug_aranges entries
can't have length zero, these can occur in the wild. There's no
particular reason to enforce this part of the spec, since functionally
they have no impact. The patch removes the error and introduces a new
warning for premature terminator entries which does not stop parsing.

This is a relanding of cb3a598c, adding the missing obj2yaml part
that was needed.

Fixes https://bugs.llvm.org/show_bug.cgi?id=46805. See also
https://reviews.llvm.org/D71932 which originally introduced the error.

Reviewed by: ikudrin, dblaikie, Higuoxing

Differential Revision: https://reviews.llvm.org/D85313