test: add a test case for the path.posix.resolve

In posix path.resolve should handle relative paths to be safe
even if process.cwd fails.

At lib/path.js#999:
    return resolvedPath.length > 0 ? resolvedPath : '.';
Else branch wasn't covered.

Add a test case to cover this.

PR-URL: #27905
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Ujjwal Sharma <usharma1998@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>
Reviewed-By: Сковорода Никита Андреевич <chalkerx@gmail.com>

test/parallel/test-path-resolve.js

@@ -69,3 +69,12 @@ if (common.isWindows) {
   const resolvedPath = spawnResult.stdout.toString().trim();
   assert.strictEqual(resolvedPath.toLowerCase(), process.cwd().toLowerCase());
 }
+
+if (!common.isWindows) {
+  // Test handling relative paths to be safe when process.cwd() fails.
+  process.cwd = () => '';
+  assert.strictEqual(process.cwd(), '');
+  const resolved = path.resolve();
+  const expected = '.';
+  assert.strictEqual(resolved, expected);
+}