Add test for EM_JS and i64 arguments

Ideally we should error out if WASM_BIGINT is not passed by I have
yet to find a good place to do that.

See #15871

Author: sbc100

tests/core/test_em_js_i64.c

@@ -0,0 +1,11 @@
+#include <stdint.h>
+#include <emscripten.h>
+
+EM_JS(void, foo, (uint64_t a, int64_t b), {
+  console.log('a:' + a);
+  console.log('b:' + b);
+})
+
+int main() {
+  foo(42000000000ull, -42ll);
+}

tests/core/test_em_js_i64.out

@@ -0,0 +1,2 @@
+a:42000000000
+b:-42

tests/test_core.py

@@ -2142,6 +2142,11 @@ def test_em_js(self, args, force_c):
     self.do_core_test('test_em_js.cpp', force_c=force_c)
     self.assertContained("no args returning int", read_file('test_em_js.js'))
 
+  def test_em_js_i64(self):
+    self.set_setting('WASM_BIGINT')
+    self.node_args += ['--experimental-wasm-bigint']
+    self.do_core_test('test_em_js_i64.c')
+
   def test_runtime_stacksave(self):
     self.do_runf(test_file('core/test_runtime_stacksave.c'), 'success')