CLSA-2023-1689701064 Fix CVE(s): CVE-2021-3737

SECURITY UPDATE: Denial of service - debian/patches/CVE-2021-3737.patch: Fix http client infinite line reading DoS after a HTTP 100 continue in Lib/httplib.py, Lib/test/testhttplib.py. - CVE-2021-3737 take building tests into account, fix failed tests - debian/patches/expat-regression.patch: fix...