[MODULARIZE=instance] Allow Module argument in --pre-js code. (#24328)

Previously we were clobbering any existing Module arguments with the
arguments passed to the `init()` function.

Also, don't limit INCOMING_MODULE_JS_API in MODULARIZE=instance mode. At
least for now I think we should go for compatibility by default.

The test I've enabled here sets the `dynamicLibraries` Module property
during in a pre-js script.

Author: sbc100

.circleci/config.yml

@@ -813,6 +813,8 @@ jobs:
             instance.test_fasta
             instance.test_EXPORTED_RUNTIME_METHODS
             instance.test_ccall
+            instance.test_dylink_basics*
+            instance.test_Module_dynamicLibraries
             esm_integration.test_fs_js_api*
             esm_integration.test_inlinejs3
             esm_integration.test_embind_val_basics

src/postamble.js

@@ -303,7 +303,7 @@ function preInit() {
 // In MODULARIZE=instance mode we delay most of the initialization work until
 // the `init` function is called.
 export default async function init(moduleArg = {}) {
-  Module = moduleArg;
+  Object.assign(Module, moduleArg);
   processModuleArgs();
 #if WASM_ESM_INTEGRATION
   updateMemoryViews();

tools/link.py

@@ -813,10 +813,10 @@ def limit_incoming_module_api():
     diagnostics.warning('experimental', '-sMODULARIZE=instance is still experimental. Many features may not work or will change.')
     if options.oformat != OFormat.MJS:
       exit_with_error('MODULARIZE instance is only compatible with ES module output format')
-    limit_incoming_module_api()
-    for s in ['wasmMemory', 'INITIAL_MEMORY']:
-      if s in settings.INCOMING_MODULE_JS_API:
-        exit_with_error(f'{s} cannot be in INCOMING_MODULE_JS_API in MODULARIZE=instance mode')
+    if 'INCOMING_MODULE_JS_API' in user_settings:
+      for s in ['wasmMemory', 'INITIAL_MEMORY']:
+        if s in settings.INCOMING_MODULE_JS_API:
+          exit_with_error(f'{s} cannot be in INCOMING_MODULE_JS_API in MODULARIZE=instance mode')
 
   if options.oformat in (OFormat.WASM, OFormat.BARE):
     if options.emit_tsd: