fix(ostool): use toolchain llvm-objcopy for bin artifacts

[ZR233]

Summary

• resolve llvm-objcopy from the active Rust toolchain instead of invoking PATH rust-objcopy in ostool runtime artifact generation
• remove the injectable ObjectTools/fake objcopy path from production and tests
• add cargo-binutils rust-objcopy comparison tests for ostool to_bin output in debug and non-debug modes
• install llvm-tools and cargo-binutils in CI for the new production path and comparison tests

Tests

• cargo fmt --all -- --check
• cargo test -p ostool
• cargo clippy --target x86_64-unknown-linux-gnu --all-features
• cargo build --target x86_64-unknown-linux-gnu --all-features