Enable v8_use_snapshot by default for 64-bit Windows cross builds

It was disabled because it didn't use to work, but it does now, see bugs.

Bug: chromium:803591, v8:9736
Change-Id: I53a04199f001b436bd5a247b51cd7c25e3a6e990
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1844776
Commit-Queue: Hans Wennborg <hans@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Auto-Submit: Hans Wennborg <hans@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#64138}

gni/v8.gni

@@ -37,12 +37,7 @@ declare_args() {
 
   # Enable the snapshot feature, for fast context creation.
   # https://v8.dev/blog/custom-startup-snapshots
-  # TODO(thakis): Make snapshots work in 64-bit win/cross builds,
-  # https://803591
-  # On Mac hosts, 32-bit builds targeting Windows can't use snapshots, see
-  # https://crbug.com/794838
-  v8_use_snapshot = !(is_win && host_os != "win" && target_cpu == "x64") &&
-                    !(is_win && host_os == "mac" && target_cpu == "x86")
+  v8_use_snapshot = true
 
   # Enable several snapshots side-by-side (e.g. default and for trusted code).
   v8_use_multi_snapshots = false