Before this CL, the heap object name of unnamed objects(those not
inheriting from NameProvider) would be solely determined by whether the
build-time configuration cppgc_enable_object_names is enabled.

This patch adds a way to override that value at runtime. This is
useful for preserving default behavior with custom builds but at the
same time allow them to still enable the feature.

Bug: chromium:1321620
Change-Id: I3aa06db15e58d9ba9773be6797572f17f007e9ee
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3620279Reviewed-by: Anton Bikineev <bikineev@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Omer Katz <omerkatz@chromium.org>
Cr-Commit-Position: refs/heads/main@{#80338}