e205929399
This is the ASan equivalent of https://github.com/llvm/llvm-project/pull/114083. The x86_64_lam_qemu buildbots started failing (https://lab.llvm.org/buildbot/#/builders/139/builds/5462/steps/2/logs/stdio). Based on the logs, it appears the ASan check is correct but it did not match the stderr/stdout output. This patch attempts to fix the issue by flushing stderr as appropriate.