Merge "Drop String::empty()" into main am: 47fc3df9a0 am: 68c2432f77 am: 17379e4315 am: b23651d7f5

Original change: https://android-review.googlesource.com/c/platform/system/core/+/2707114

Change-Id: I128b8ddf078cb7a4e8fe4ff2328af883e5338f3d
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>