Revert "Update zlib to 1.2.11"

This reverts commit fbe84be2.

This causes issues with server side infrastructure that makes invasive
assumptions about the nature of compressed zlib output at each compression
level which was broken by the upgrade from 1.2.8 -> 1.2.11. As a result, the
upgrade is being temporarily reverted to give the teams involved a little
more time to fix the issues on their end.

Bug: 38369364
Test: run cts -m CtsLibcoreTestCases
Change-Id: Idb366813f4f1063babcd5002e99555d2f5a2bbd6