move fuzz from UtaskLocalExecutor to Utask

[javanlacerda]

Tries to fix b/446692241.

The fuzz task for black box fuzzer are failing on Batch.

Error stacktrace:

node:internal/fs/utils:347
    throw err;
    ^

Error: ENOENT: no such file or directory, scandir '/mnt/scratch0/clusterfuzz/bot/inputs/fuzzer-common-data-bundles/v8'
    at Object.readdirSync (node:fs:1450:3)
    at Object.readdirSync (pkg/prelude/bootstrap.js:1306:35)
    at walkDirectory (/snapshot/js_fuzzer/corpus.js:27:29)
    at walkDirectory.next (<anonymous>)
    at V8Corpus.create (/snapshot/js_fuzzer/corpus.js:91:16)
    at Object.create (/snapshot/js_fuzzer/corpus.js:333:49)
    at new RandomCorpusRunner (/snapshot/js_fuzzer/runner.js:81:20)
    at new RandomCorpusRunnerWithFuzzilli (/snapshot/js_fuzzer/runner.js:112:5)
    at ScriptMutator.createRunner (/snapshot/js_fuzzer/script_mutator.js:122:12)
    at main (/snapshot/js_fuzzer/run.js:121:26)
    at Object.<anonymous> (/snapshot/js_fuzzer/run.js:159:1)
    at Module._compile (pkg/prelude/bootstrap.js:1926:22)
    at Module._extensions..js (node:internal/modules/cjs/loader:1166:10)
    at Module.load (node:internal/modules/cjs/loader:988:32)
    at Module._load (node:internal/modules/cjs/loader:834:12)
    at Function.runMain (pkg/prelude/bootstrap.js:1979:12)
    at node:internal/main/run_main_module:17:47 {
  errno: -2,
  syscall: 'scandir',
  code: 'ENOENT',
  path: '/mnt/scratch0/clusterfuzz/bot/inputs/fuzzer-common-data-bundles/v8'
}

Node.js v18.5.0

It seems the cause it that the v8 directory was not created, and it depends on downloading it from GCS. Then the suspicious is that the batch execution is not able to download.

This PR attempts to solve this by moving the fuzz task command type to UTask, as it has the remote way to work, being able to download the required stuff and keeping the local execution as fallback.

[ViniciustCosta]

Not sure about all the implications from this change, we need to check if this works for batch and for fuzz running on GCE bots (for Chrome).