Upgrade builtin-actors and ref-fvm?

[sanderpick]

Hey guys, are there any blockers in updating to the latest builtin-actors? I ask because...

• ipc relies on builtin-actors tag v12.0.0, which relies on ref-fvm version 4.0.0-alpha.4
• ipc relies on ref-fvm version 4.1.0, which is a little awkward

However, what led me here is that ref-fvm 4.1.0 (and I'm guessing 4.0.0-alpha.4 but can't verify because there is no corresponding tag), relies on wasmtime 12.0.2, which breaks with rust 1.82.0. Specifically, the actor bundles can't be loaded. Wasmtime throws an error:

2024-10-21T17:08:31.773610Z ERROR fendermint/app/src/main.rs:45: failed to execute Options { home_dir: "~/.fendermint", config_dir: None, mode: "dev", global: GlobalArgs { network: Testnet }, command: Genesis(GenesisArgs { genesis_file: "test-network/genesis.json", command: Ipc { command: SealGenesis(SealGenesisArgs { builtin_actors_path: "/home/sander/.fendermint/bundle.car", custom_actors_path: "/home/sander/.fendermint/custom_actors_bundle.car", artifacts_path: Some("/home/sander/.fendermint/contracts"), output_path: "test-network/sealed_genesis.car" }) } }) }: failed to init exec state

Caused by:
    0: failed to create exec state
    1: could not prepare actor with code CID bafk2bzacedzossdursdb5w4jfuyrv6fm3cznzmee3kkaqzr3aaba5gmhy7npu
    2: failed to validate actor wasm
    3: reference-types not enabled: zero byte expected (at offset 0x2b473)

See bytecodealliance/wasmtime#9130
See bytecodealliance/wasmtime#9162

Pre-wasmtime 25.0.0, the trick is to enable the gc feature which somehow enables wasm reference-types. Apparently, post-wasmtime 25.0.0, this is no longer needed. However, the version used by ref-fvm (12.0.2), does not have the gc feature. There must be some other way to fix this with the old wasmtime, but I think ideally we can just use latest builtin-actors with latest ref-fvm.

Looks like support for wasmtime 25.0.2 just landed in ref-fvm v4.4.3. Maybe a good time to try for an update?