This PR was split from https://github.com/llvm/llvm-project/pull/137228 (which introduced support for `DW_TAG_module` and `DW_AT_byte_size`). This PR improves `LVDWARFReader` by introducing handling of `DW_AT_byte_size`. Most DWARF emitters include this attribute for types to specify the size of an entity of the given type.