in modules.cpp:

static PackageEntry* get_package_entry_by_name(Symbol* package,
                                               Handle h_loader,
                                               TRAPS) {
  if (package != NULL) {
    ResourceMark rm(THREAD);
    if (Modules::verify_package_name(package->as_C_string())) {
      PackageEntryTable* const package_entry_table =
        get_package_entry_table(h_loader);
      assert(package_entry_table != NULL, "Unexpected null package entry table");
      return package_entry_table->lookup_only(package);
    }
  }
  return NULL;
}

Since the package lookup would fail for any invalid package name, the call to verify_package_name appears pointless.