Restructure test files (#10415)

tests/format/js/function-first-param/function_expression.js

@@ -0,0 +1,25 @@
+//https://github.com/prettier/prettier/issues/3002
+beep.boop().baz("foo",
+{
+  some: {
+    thing: {
+      nested: true
+    }
+  }
+},
+{ another: { thing: true } },
+() => {});
+
+
+//https://github.com/prettier/prettier/issues/2984
+db.collection('indexOptionDefault').createIndex({ a: 1 }, {
+  indexOptionDefaults: true,
+  w: 2,
+  wtimeout: 1000
+}, function(err) {
+  test.equal(null, err);
+  test.deepEqual({ w: 2, wtimeout: 1000 }, commandResult.writeConcern);
+
+  client.close();
+  done();
+});