Cross Reference: /external/libcxx/test/std/strings/basic.string/string.nonmembers/string_op+

`Name`	`Date`	`Size`
Up to higher level directory
`char_string.pass.cpp`	06-Dec-2017	`2.2K`
`pointer_string.pass.cpp`	06-Dec-2017	`5.5K`
`string_char.pass.cpp`	06-Dec-2017	`2.2K`
`string_pointer.pass.cpp`	06-Dec-2017	`5.5K`
`string_string.pass.cpp`	06-Dec-2017	`10.6K`