In upcoming work these flags will be used to configure the
experimental native context independent code feature.

Build-time flags:

v8_enable_nci_code

Defines:

V8_ENABLE_NCI_CODE

Runtime flags:

--turbo-nci
--turbo-nci-as-highest_tier
--print-nci-code
--trace-turbo-nci

Drive-by: Remove unused embedded builtins and jitless defines.

Bug: v8:8888
Change-Id: I4466b440634a787bd84b052fe2466b22540216a4
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2184295Reviewed-by: Georg Neis <neis@chromium.org>
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67650}