read from zero register in RISCV should always return 0

[Kyle-Kyle]

Description

Currently, GET:I64(zero) will not be resolved to 0, instead, it will read the symbolic value in the register

Steps to reproduce the bug

No response

Environment

No response

Additional context

No response

[Kyle-Kyle]

An example can be found here: https://github.com/angr/binaries/blob/feat/ng/tests/riscv/borgbackup2-chunker.cpython-312-riscv64-linux-gnu.so
address 0x0000000000011f32