Merge kselftest from Linux 5.5

Bug: 79702574
Test: kselftest on cuttlefish 5.4 and 4.19
Test: kselftest on flame (4.14)

Change-Id: I01a6acbf32d5b2c6e8816eb1d4a21d88d94fcb1e
Signed-off-by: Steve Muckle <smuckle@google.com>