Merge "fiemap: support FIEMAP_EXTENT_MERGED" am: 286e5aba63

Original change: https://android-review.googlesource.com/c/platform/system/core/+/1590474

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I46a34fe7939ec85f66be4b7d458dd117d0e2f40d