[bazel] Fix build on arm64.

Missed in https://crrev.com/c/3337367.
Signed-off-by: Piotr Sikora <piotrsikora@google.com>
Change-Id: I32363a5a4282a9e32ad71ae12ec6e4d9def40f96
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3368870Reviewed-by: Victor Gomes <victorgomes@chromium.org>
Commit-Queue: Victor Gomes <victorgomes@chromium.org>
Cr-Commit-Position: refs/heads/main@{#78510}

bazel/defs.bzl

@@ -370,6 +370,7 @@ def _v8_target_cpu_transition_impl(settings, attr):
         "x64_windows": "x64",
         "x86": "ia32",
         "ppc": "ppc64",
+        "aarch64": "arm64",
         "arm64-v8a": "arm64",
         "arm": "arm64",
         "armeabi-v7a": "arm32",