CIPD: Add aarch64 string to detect native ARM.

That's what platform.machine reports in Ubuntu Linux,
causing failure to build on ARM.

Change-Id: I739faec6779b6f0781ba3a72d264a055bd465ac4
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/314115
Reviewed-by: Kai Ninomiya <kainino@chromium.org>
Commit-Queue: Kai Ninomiya <kainino@chromium.org>
Reviewed-by: Brian Sheedy <bsheedy@google.com>
Commit-Queue: Brian Sheedy <bsheedy@google.com>

tools/python/cipd_deps.py

diff --git a/tools/python/cipd_deps.py b/tools/python/cipd_deps.py
index fefd344..3d0befe 100644
--- a/tools/python/cipd_deps.py
+++ b/tools/python/cipd_deps.py
@@ -64,7 +64,7 @@
 
     The returned string is compatible with CIPD's package naming scheme.
     """
-    native_arm = platform.machine().lower() in ('arm', 'arm64')
+    native_arm = platform.machine().lower() in ('arm', 'arm64', 'aarch64')
     # This is necessary for the case of running x86 Python on arm devices via
     # an emulator. In this case, platform.machine() will show up as an x86
     # processor.