[Analyzer] Fix the Z3 lit test config

Summary:
The '%analyze' extra_args config argument seems to have been erroneously
deleted in r315627 disabling Z3 tests for the clang analyzer. Add the
flag back.

Reviewers: george.karpenkov, NoQ, ddcc

Reviewed By: george.karpenkov

Subscribers: xazax.hun, szepet, delcypher, a.sidorin, llvm-commits

Differential Revision: https://reviews.llvm.org/D47722

llvm-svn: 334066