[clang] [clang][analysis] Fix flaky clang/test/Analysis/live-stmts.cpp test (PR #126913)

[Balazs Benics via cfe-commits]

steakhal wrote:

FYI I just [merged](https://github.com/llvm/llvm-project/commit/f378e52ed3c6f8da4973f97f1ef043c2eb0da721) my second attempt of enabling and fixing the flaky test. Let me know if it works.

https://github.com/llvm/llvm-project/pull/126913