Revert of Move SkPixelXorXfermode.h to include/client/android (patchset #5 id:80001...

Revert of Move SkPixelXorXfermode.h to include/client/android (patchset #5 id:80001 of https://codereview.chromium.org/1645093002/ )

Reason for revert:
GN woes

Original issue's description:
> Move SkPixelXorXfermode.h to include/client/android
>
> This intended to make clients aware that the SkPixelXorXfermode is Android-specific
>
> GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1645093002
>
> Committed: https://skia.googlesource.com/skia/+/aa9cb62901075e9d2858353cb041e5e6d4719614

TBR=scroggo@google.com,reed@google.com,djsollen@google.com
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Review URL: https://codereview.chromium.org/1644903004