Use zip_cmd() and unzip_cmd() in update_node.py as well. (#1471)

This way update_node.py can be called on Windows host machines as well.

scripts/zip.py

@@ -0,0 +1,18 @@
+import os
+
+def unzip_cmd():
+    # Use 7-Zip if available (https://www.7-zip.org/)
+    sevenzip = os.path.join(os.getenv('ProgramFiles', ''), '7-Zip', '7z.exe')
+    if os.path.isfile(sevenzip):
+        return [sevenzip, 'x']
+    # Fall back to 'unzip' tool
+    return ['unzip', '-q']
+
+
+def zip_cmd():
+    # Use 7-Zip if available (https://www.7-zip.org/)
+    sevenzip = os.path.join(os.getenv('ProgramFiles', ''), '7-Zip', '7z.exe')
+    if os.path.isfile(sevenzip):
+        return [sevenzip, 'a', '-mx9']
+    # Fall back to 'zip' tool
+    return ['zip', '-rq']