wasm: support js string constant esm import

doc/api/esm.md

@@ -809,6 +809,15 @@ imports and they cannot be inspected via `WebAssembly.Module.imports(mod)`
 or virtualized unless recompiling the module using the direct
 `WebAssembly.compile` API with string builtins disabled.
 
+String constants may also be imported from the `wasm:js/string-constants` builtin
+import URL, allowing static JS string globals to be defined:
+
+```text
+(module
+  (import "wasm:js/string-constants" "hello" (global $hello externref))
+)
+```
+
 Importing a module in the source phase before it has been instantiated will also
 use the compile-time builtins automatically:
 

lib/internal/modules/esm/translators.js

@@ -522,6 +522,7 @@
   try {
     compiled = new WebAssembly.Module(source, {
       builtins: ['js-string'],
+      importedStringConstants: "wasm:js/string-constants",
     });
   } catch (err) {
     err.message = errPath(url) + ': ' + err.message;

test/fixtures/es-modules/js-string-builtins.wat

@@ -4,11 +4,15 @@
   (import "wasm:js-string" "length" (func $string_length (param externref) (result i32)))
   (import "wasm:js-string" "concat" (func $string_concat (param externref externref) (result (ref extern))))
   (import "wasm:js-string" "equals" (func $string_equals (param externref externref) (result i32)))
+
+  ;; Import a string constant via importedStringConstants
+  (import "wasm:js/string-constants" "hello" (global $hello externref))
 
   ;; Export functions that use the builtins
   (export "getLength" (func $get_length))
   (export "concatStrings" (func $concat_strings))
   (export "compareStrings" (func $compare_strings))
+  (export "getHello" (func $get_hello))
 
   (func $get_length (param $str externref) (result i32)
     local.get $str
@@ -26,4 +30,8 @@
     local.get $str2
     call $string_equals
   )
+
+  (func $get_hello (result externref)
+    global.get $hello
+  )
 )

test/fixtures/es-modules/test-wasm-js-string-builtins.mjs

@@ -6,3 +6,4 @@ strictEqual(wasmExports.getLength('hello'), 5);
 strictEqual(wasmExports.concatStrings('hello', ' world'), 'hello world');
 strictEqual(wasmExports.compareStrings('test', 'test'), 1);
 strictEqual(wasmExports.compareStrings('test', 'different'), 0);
+strictEqual(wasmExports.getHello(), 'hello');