Merge "core: Move FastXmlSerializer to module utils" into udc-dev-plus-aosp am: 525720bf5a

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/25315861

Change-Id: I862ed2fea93f7f2dce97da19f5e4e55703fc1fab
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>