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`	21-Aug-2018	`2.1K`
`pointer_string.pass.cpp`	21-Aug-2018	`5.4K`
`string_char.pass.cpp`	21-Aug-2018	`2.1K`
`string_pointer.pass.cpp`	21-Aug-2018	`5.4K`
`string_string.pass.cpp`	21-Aug-2018	`10.8K`