bpo-28494: install ziptestdata to fix install bot (GH-15902)

diff --git a/Makefile.pre.in b/Makefile.pre.in
index 4f4f096..1c0958e 100644
--- a/Makefile.pre.in
+++ b/Makefile.pre.in
@@ -1374,6 +1374,7 @@
 		test/test_importlib/source \
 		test/test_importlib/zipdata01 \
 		test/test_importlib/zipdata02 \
+		test/ziptestdata \
 		asyncio \
 		test/test_asyncio \
 		collections concurrent concurrent/futures encodings \