This is a reland of 712b66da

Breakage is fixed on infra side by:
https://crrev.com/c/983417

Original change's description:
> [build] Remove legacy isolate configurations
>
> Bug: chromium:669910
> Cq-Include-Trybots: luci.v8.try:v8_linux_noi18n_rel_ng
> Change-Id: Iad58563fd4bb35501493f88af83362b1206a186c
> Reviewed-on: https://chromium-review.googlesource.com/982630
> Reviewed-by: Sergiy Byelozyorov <sergiyb@chromium.org>
> Commit-Queue: Michael Achenbach <machenbach@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#52267}

Bug: chromium:669910
Change-Id: I6c06a1fe9587206aa4e983befb105327bfec4154
Cq-Include-Trybots: luci.v8.try:v8_linux_noi18n_rel_ng
Reviewed-on: https://chromium-review.googlesource.com/983573Reviewed-by: Sergiy Byelozyorov <sergiyb@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52273}