Build realloc-clock SBF in tests and remove bundled artifact

[jflatow]

Motivation

• Remove the committed SBF shared-object artifact because bundling the .so in the repo is not supported and leads to stale artifacts.
• Provide a small SBF test program that exercises realloc and the Clock sysvar so the Deno bindings can call real syscalls during tests.
• Ensure Deno tests build the SBF program at test time to keep the binary and tests synchronized.

Description

• Removed the bundled realloc_clock.so from crates/deno-litesvm/program_bytes and updated the Deno test to load the locally-built binary at ../litesvm/test_programs/target/deploy/realloc_clock.so in crates/deno-litesvm/syscall_clock.test.ts.
• Added a new SBF test program realloc-clock under crates/litesvm/test_programs/ with a Cargo.toml and src/lib.rs implementing process_instruction that computes a checksum over a realloc-sized buffer and reads Clock::get() into account data.
• Added realloc-clock to the crates/litesvm/test_programs workspace and updated the lockfile entries accordingly.
• Updated crates/deno-litesvm/Makefile to run cargo build-sbf (configurable via SBF_BUILD_FLAGS) in the test target before invoking deno test so the program is built automatically.

Testing

• Ran cargo build-sbf --skip-tools-install --manifest-path ../litesvm/test_programs/realloc-clock/Cargo.toml, which completed successfully and produced the deployable .so.
• Ran deno test -A --unsafely-ignore-certificate-errors mod.test.ts client.test.ts syscall_clock.test.ts, which completed successfully.
• Executed the make test workflow in crates/deno-litesvm, which required installing cargo-build-sbf in the environment and then succeeded when re-run.

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Codex Task