[test] Add more testing for instantiateWasm module API. NFC (#23577)

See #23572

Author: sbc100

test/test_browser.py

@@ -4208,9 +4208,10 @@ def test_async_compile(self, opts, returncode):
   # Test that implementing Module.instantiateWasm() callback works.
   @also_with_asan
   def test_manual_wasm_instantiate(self):
-    self.compile_btest('test_manual_wasm_instantiate.c', ['-o', 'manual_wasm_instantiate.js'])
+    self.set_setting('EXIT_RUNTIME')
+    self.compile_btest('test_manual_wasm_instantiate.c', ['-o', 'manual_wasm_instantiate.js'], reporting=Reporting.JS_ONLY)
     shutil.copy(test_file('test_manual_wasm_instantiate.html'), '.')
-    self.run_browser('test_manual_wasm_instantiate.html', '/report_result?1')
+    self.run_browser('test_manual_wasm_instantiate.html', '/report_result?exit:0')
 
   def test_wasm_locate_file(self):
     # Test that it is possible to define "Module.locateFile(foo)" function to locate where worker.js will be loaded from.

test/test_manual_wasm_instantiate.c

@@ -3,14 +3,13 @@
 // University of Illinois/NCSA Open Source License.  Both these licenses can be
 // found in the LICENSE file.
 
+#include <assert.h>
 #include <stdio.h>
-#include <emscripten/emscripten.h>
+#include <emscripten/em_asm.h>
 
-int main()
-{
-	printf("OK\n");
-#ifdef REPORT_RESULT
-	int result = EM_ASM_INT({return Module.testWasmInstantiationSucceeded;});
-	REPORT_RESULT(result);
-#endif
+int main() {
+  printf("in main\n");
+  int result = EM_ASM_INT({return Module.testWasmInstantiationSucceeded;});
+  assert(result);
+  return 0;
 }

test/test_other.py

@@ -15542,3 +15542,18 @@ def test_invalid_export_name(self):
     create_file('test.c', '__attribute__((export_name("my.func"))) void myfunc() {}')
     err = self.expect_fail([EMCC, 'test.c'])
     self.assertContained('emcc: error: invalid export name: my.func', err)
+
+  def test_instantiate_wasm(self):
+    create_file('pre.js', '''
+      Module['instantiateWasm'] = (imports, successCallback) => {
+        var wasmFile = findWasmBinary();
+        getWasmBinary(wasmFile).then((bytes) => {
+          WebAssembly.instantiate(bytes, imports).then((res) => {
+            out('wasm instantiation succeeded');
+            Module['testWasmInstantiationSucceeded'] = 1;
+            successCallback(res.instance, res.module);
+          });
+        });
+        return {}; // Compiling asynchronously, no exports.
+      }''')
+    self.do_runf('test_manual_wasm_instantiate.c', emcc_args=['--pre-js=pre.js'])