bpo-33125: Add support for building and releasing Windows ARM64 packages (GH-16828)

Note that the support is not actually enabled yet, and so we won't be publishing these packages. However, for those who want to build it themselves (even by reusing the Azure Pipelines definition), it's now relatively easy to enable.
diff --git a/PCbuild/build.bat b/PCbuild/build.bat
index bce5993..623409c 100644
--- a/PCbuild/build.bat
+++ b/PCbuild/build.bat
@@ -57,7 +57,7 @@
 set target=Build
 set dir=%~dp0
 set parallel=/m
-set verbose=/nologo /v:m
+set verbose=/nologo /v:m /clp:summary
 set kill=
 set do_pgo=
 set pgo_job=-m test --pgo