script: Check if IndexedDB key path is ECMAScript identifier name (#39255)

From IndexedDB spec, when we check whether a key path is valid, we have
to check whether it is an ECMAScript identifier name. We have not yet
implemented this logic, and always return true.

This patch uses the function `js::rust::wrappers::JS_IsIdentifier` to
achieve this checking.

Testing: Pass WPT tests that were expected to fail.
Fixes: #25324

---------

Signed-off-by: Kingsley Yung <kingsley@kkoyung.dev>

components/script/dom/idbdatabase.rs

@@ -211,7 +211,7 @@ impl IDBDatabaseMethods<crate::DomTypeHolder> for IDBDatabase {
 
         // Step 5
         if let Some(path) = key_path {
-            if !is_valid_key_path(path) {
+            if !is_valid_key_path(path)? {
                 return Err(Error::Syntax(None));
             }
         }