[LLDB][RISCV] Add RISC-V ArchSpec and rv32/rv64 variant detection
Adds the RISC-V ArchSpec bits contributed by @simoncook as part of D62732,
plus logic to distinguish between riscv32 and riscv64 based on ELF class.
The patch follows the implementation approach previously used for MIPS.
It defines RISC-V architecture subtypes and inspects the ELF header,
namely the ELF class, to detect the right subtype.
Differential Revision: https://reviews.llvm.org/D86292
GitOrigin-RevId: 15f5971150684b656005cfd5b744c1a34477ff60
4 files changed
