LibWasm: Make local_tee validation keep the value on the stack

Author: https://github.com/alimpfard
Commit: https://github.com/SerenityOS/serenity/commit/6e07e74261
Pull-request: https://github.com/SerenityOS/serenity/pull/13770
Reviewed-by: https://github.com/sin-ack ✅

Userland/Libraries/LibWasm/AbstractMachine/Validator.cpp

@@ -1420,6 +1420,7 @@ VALIDATE_INSTRUCTION(local_tee)
 
     auto& value_type = m_context.locals[index.value()];
     TRY(stack.take(value_type));
+    stack.append(value_type);
 
     return {};
 }