Don't use deprecated HTML Imports, directly fetch the template files from
html instead.

Bug: v8:10155
Change-Id: Ic85a8b2cf227231fc6abf5adca6f1f144bf728f2
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2113371Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66825}