Refactor readobj to integrate AArch64 Build Attributes under
ELFAttributeParser. ELFAttributeParser now serves as a base class for:
- ELFCompactAttrParser, handling Arm-style attributes with a single
build attribute subsection.
- ELFExtendedAttrParser, handling AArch64-style attributes with multiple
build attribute subsections. This improves code organization and better
aligns with the attribute parsing model.
Add support for parsing AArch64 Build Attributes.
Defines a subset of attributes and emits them to a section called
.hexagon.attributes.
The current attributes recorded are the attributes needed by
llvm-objdump to automatically determine target features and eliminate
the need to manually pass features.
