Enable fuzzing for relaxed atomics

[stevenfontanella]

Part of #8165. V8 now supports relaxed atomics with the --experimental-wasm-acquire-release flag.

cc @rmahdav

[kripken]

lgtm, though I wonder if this might start to fuzz testcases with wait/notify, and cause hangs? I'm not sure what testcases we have for this feature. And do we generate anything for it in fuzzing.cpp?

But if you run the fuzzer for a while and things seem ok, it's probably fine.

[stevenfontanella]

lgtm, though I wonder if this might start to fuzz testcases with wait/notify, and cause hangs? I'm not sure what testcases we have for this feature. And do we generate anything for it in fuzzing.cpp?

But if you run the fuzzer for a while and things seem ok, it's probably fine.

Wait and notify aren't part of the proposal, see the spec test. I'll fuzz for a few hours before submitting.

[stevenfontanella]

Ran the fuzzer for 5000 iterations from dcc8843 with no issues.