Migrate root .vpython3 and tools/.vpython3 specifications to modern
vpython.toml and generated vpython.toml.uv.lock files (FlowUV / UV).
Updates isolate inputs in BUILD.gn (v8_python_base) and tools/BUILD.gn
(v8_testrunner), along with DEPS hook (vpython3_common) and OWNERS.
Pins setuptools in vpython.toml dependencies to support pkg_resources
imports required by mock 2.0.0 and pbr 3.0.0 in UV environments.
NO_IFTTT=v8_python_base and isolate vpython specs are not present in Bazel build
TAG=agy
CONV=b53bdf70-37e7-4696-be50-8ee6fc19b1f8
LSC: go/vpython-uv-config-lsc
Bug: 491263752
Change-Id: Iacdc0aaf6f678f3b60c66110d288bdbd0bc93ffc
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/8408966
Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Commit-Queue: Alex Ovsienko <ovsienko@google.com>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/main@{#109869}
