In file include/v8config.h we define:

ifdef V8_OS_WIN
...
if defined(_M_X64) || defined(__x86_64__)
  define V8_OS_WIN_X64 true
endif

and V8_OS_WIN_X64 is supposed to be defined when targeting X64 on Windows only.
But this is wrong because V8_OS_WIN_X64 gets defined also on an ARM64 builds
when the host machine is X64. It should instead be:

ifdef V8_OS_WIN
...
if defined(V8_TARGET_ARCH_X64)
  define V8_OS_WIN_X64 true
endif

Bug: v8:9090
Change-Id: I88e4c46bb6df1efa2070d4e1785081d71df96f0e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1554222Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Paolo Severini <paolosev@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#60758}