Ensure the patches are up-to-date and consistent

Add the update-patches.py tool.

Update all the patches, so that the files are up-to-date and use the
same patch file format.

patches/patches/026_hello2.patch

@@ -1,4 +1,4 @@
-22c22
+26c26
 <     stdout.print("Hello world!\n", .{});
 ---
 >     try stdout.print("Hello world!\n", .{});