fix: skip empty __exportAll call

Author: sxzz

src/fake-js.ts

@@ -972,6 +972,7 @@ function patchTsNamespace(nodes: t.Statement[]) {
     if (!result) continue
 
     const [binding, exports] = result
+    if (!exports.properties.length) continue
 
     nodes[i] = {
       type: 'TSModuleDeclaration',

tests/__snapshots__/index.test.ts.snap

@@ -422,9 +422,7 @@ exports[`re-export from lib > both 1`] = `
 export * from "stub-lib";
 
 //#region \\0rolldown/runtime.js
-declare namespace a_d_exports {
-  export {};
-}
+
 import * as import_stub_lib from "stub-lib";
 //#endregion
 export { import_stub_lib as t };
@@ -441,9 +439,6 @@ export * from "stub-lib";"
 
 exports[`re-export from lib > onlyB 1`] = `
 "// b.d.ts
-declare namespace a_d_exports {
-  export {};
-}
 import * as import_stub_lib from "stub-lib";
 type LibType = import_stub_lib.LibType;
 export { type LibType };"