Charge syscall gas inside wasm instrumentation

[Stebalien]

Currently, we charge a flat "syscall" gas on every syscall here:

ref-fvm/fvm/src/syscalls/bind.rs

Line 127 in 9c35c30

charge_syscall_gas!(data.kernel);

However, we should be charging this gas before making the syscall to avoid letting an attacker perform an operation where it can't quite cover the gas.

Right now, it's not really an issue because we can only run into this situation once per message. However, with gas limits on internal sends (#966), it may be possible to trigger this multiple times.

Of course, it's not a huge issue because an attacker could only do this once per send, but it's still something we should look into.

[Stebalien]

cc @raulk because it relates to #1149.

[Stebalien]

Action: Look into this while the testnet is running and consider fixing. We will likely punt to M2.2.