Merge "Don't discard the result of std::unique" into main am: d0210ae77c am: cffa43f6df am: 2e32ff5e4e am: 1648e07c61

Original change: https://android-review.googlesource.com/c/platform/external/clang/+/2755601

Change-Id: Idefa102d2bee9dd334a8f5d361ac4f6bef12428a
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>