test: try fix tmp

Author: sumimakito

packages/duckdb-wasm/.gitignore

@@ -6,4 +6,5 @@
 /duckdb_webapi.*
 /dist
 /docs
+/test_temp
 *.d.ts.map

packages/duckdb-wasm/test/nodefs.test.ts

@@ -1,8 +1,14 @@
 import * as duckdb from '../src/';
-import { tmpdir } from 'os';
 import { randomUUID } from 'crypto';
-import path from 'path';
 import { unlink } from 'fs/promises';
+import { mkdirSync } from 'fs';
+import path from 'path';
+
+const tmpdir = () => {
+    const tmp = path.resolve(__dirname, '../test_temp');
+    mkdirSync(tmp, { recursive: true });
+    return tmp;
+}
 
 export function testNodeFS(db: () => duckdb.AsyncDuckDB): void {
     const files: string[] = [];