src: omit unconvertible names in cjs_lexer::Parse

[anonrig]

Follow-up to #63885 (aa25a0a30c3).

That change made CreateString() return a MaybeLocal<String> and bailed out of Parse() (early return) when an export / re-export name could not be converted to a V8 string or when Set::Add() failed. Because the binding then returns undefined, the JS caller (cjsPreparseModuleExports in lib/internal/modules/esm/translators.js, which does const { 0: exportNames, 1: reexports } = cjsParse(source)) fails the entire exports preparse for that module.

This makes the conversion best-effort instead: omit any individual export / re-export name that cannot be turned into a V8 string and continue, so the remaining names are still returned and a single pathological name no longer fails the whole preparse. Set::Add() is a V8_WARN_UNUSED_RESULT, so its result is explicitly discarded with USE().

for (const auto& exp : analysis.exports) {
  Local<String> exp_str;
  if (CreateString(isolate, exp).ToLocal(&exp_str)) {
    USE(exports_set->Add(context, exp_str));
  }
}

Verified locally: node_cjs_lexer.cc builds clean, cpplint passes, the cjs_lexer binding returns the expected export/re-export names (ASCII + non-ASCII) and handles null/empty input, and test/es-module CJS-exports tests pass.

Refs: #63885
Refs: #63323

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/74186/