[automerger skipped] DO NOT MERGE Use explicitly opened file with O_WRONLY in test_sendfile_errno am: f0324559dd -s ours am: b800078f99 -s ours

am skip reason: subject contains skip directive

Original change: https://android-review.googlesource.com/c/platform/libcore/+/2241795

Change-Id: Ifbed8188bad52131ed9978e94a911086b5593603
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>