worker: fix --abort-on-uncaught-exception handling

The `set_abort_on_uncaught_exception(false)` line was supposed to
prevent aborting when running Workers in
`--abort-on-uncaught-exception` mode, but it was incorrectly set
and not checked properly in the should-abort callback.

src/api/environment.cc

@@ -43,6 +43,7 @@ static bool ShouldAbortOnUncaughtException(Isolate* isolate) {
   Environment* env = Environment::GetCurrent(isolate);
   return env != nullptr &&
          (env->is_main_thread() || !env->is_stopping()) &&
+         env->abort_on_uncaught_exception() &&
          env->should_abort_on_uncaught_toggle()[0] &&
          !env->inside_should_not_abort_on_uncaught_scope();
 }

src/env.cc

@@ -359,7 +359,7 @@ Environment::Environment(IsolateData* isolate_data,
   inspector_host_port_.reset(
       new ExclusiveAccess<HostPort>(options_->debug_options().host_port));
 
-  if (flags & EnvironmentFlags::kOwnsProcessState) {
+  if (!(flags_ & EnvironmentFlags::kOwnsProcessState)) {
     set_abort_on_uncaught_exception(false);
   }
 

test/parallel/test-worker-abort-on-uncaught-exception.js

@@ -0,0 +1,12 @@
+// Flags: --abort-on-uncaught-exception
+'use strict';
+const common = require('../common');
+const assert = require('assert');
+const { Worker } = require('worker_threads');
+
+// Tests that --abort-on-uncaught-exception does not apply to
+// Workers.
+
+const w = new Worker('throw new Error()', { eval: true });
+w.on('error', common.mustCall());
+w.on('exit', common.mustCall((code) => assert.strictEqual(code, 1)));