When enabled, this API exposes a new global 'Sandbox' object which
contains a number of functions and objects that in effect emulate
typical memory corruption primitives constructed by exploits. In
particular, the 'MemoryView' constructor can construct ArrayBuffers
instances that can corrupt arbitrary memory inside the sandbox. Further,
the getAddressOf(obj) and getSizeInBytesOf(obj) functions can be used
respectively to obtain the address (relative to the base of the sandbox)
and size of any HeapObject that can be accessed from JavaScript.

This API is useful for testing the sandbox, for example to
facilitate developing PoC sandbox escapes or writing regression tests.
In the future, it may also be used by custom V8 sandbox fuzzers.

Bug: v8:12878
Change-Id: I4e420b2ff28bd834b0693f1546942e51c71bfdda
Cq-Include-Trybots: luci.v8.try:v8_linux64_heap_sandbox_dbg_ng,v8_linux_arm64_sim_heap_sandbox_dbg_ng
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3650718Reviewed-by: Igor Sheludko <ishell@chromium.org>
Commit-Queue: Samuel Groß <saelo@chromium.org>
Cr-Commit-Position: refs/heads/main@{#80659}