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

am skip reason: subject contains skip directive

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

Change-Id: I73af67ecdb6e1ef0e653c0e533e62c610f798d90
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>