Fix use-after-free in SurfaceFlinger::doDump am: 3b3e59185d

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/native/+/20065076

Change-Id: Iadc12337786e96db977dfa7e904e0f799d2f12e4
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>