Without this, asan (rightfully) complains about read-only space leaking.

Because pages are manually allocated using mmap, a few objects within
them need to be explicitly ignored in addition to the read-only heap
itself.

This change re-adds lsan.h, with tweaks to make the type checking a bit
more lenient.

Bug: v8:7464
Change-Id: I0e2809930f3674e3f891e755b568ebb5194da461
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1622121Reviewed-by: Dan Elphick <delphick@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Maciej Goszczycki <goszczycki@google.com>
Cr-Commit-Position: refs/heads/master@{#61942}