Added more test cases which common js libraries uses .pipe()

javascript/ql/test/query-tests/Quality/UnhandledStreamPipe/execa.js

@@ -0,0 +1,11 @@
+const execa = require('execa');
+
+(async () => {
+  const first = execa('node', ['empty.js']);
+  const second = execa('node', ['stdin.js']);
+
+  first.stdout.pipe(second.stdin); // $SPURIOUS:Alert
+
+  const {stdout} = await second;
+  console.log(stdout);
+})();