test: add coverage for _exceptionWithHostPort

Add test case for util._exceptionWithHostPort function to verify
proper error object creation with correct properties and message
formatting.

Author: SeokhunEom

test/parallel/test-uv-unmapped-exception.js

@@ -3,6 +3,9 @@
 require('../common');
 const assert = require('assert');
 const { UVException, UVExceptionWithHostPort } = require('internal/errors');
+const { _exceptionWithHostPort } = require('util');
+const { internalBinding } = require('internal/test/binding');
+const uv = internalBinding('uv');
 
 {
   const exception = new UVException({ errno: 100, syscall: 'open' });
@@ -24,3 +27,14 @@ const { UVException, UVExceptionWithHostPort } = require('internal/errors');
   assert.strictEqual(exception.address, '127.0.0.1');
   assert.strictEqual(exception.port, 80);
 }
+
+{
+  const err = _exceptionWithHostPort(uv.UV_EADDRINUSE, 'bind', '127.0.0.1', 8080);
+  assert(err instanceof Error);
+  assert.strictEqual(err.code, 'EADDRINUSE');
+  assert.strictEqual(err.errno, uv.UV_EADDRINUSE);
+  assert.strictEqual(err.syscall, 'bind');
+  assert.strictEqual(err.address, '127.0.0.1');
+  assert.strictEqual(err.port, 8080);
+  assert.strictEqual(err.message, 'bind EADDRINUSE 127.0.0.1:8080');
+}