Cross Reference: /external/libcxx/test/std/input.output/string.streams/stringbuf/stringbuf.assign

`Name`	`Date`	`Size`
Up to higher level directory
`member_swap.pass.cpp`	22-Oct-2020	`1.7K`
`move.pass.cpp`	22-Oct-2020	`1.5K`
`nonmember_swap.pass.cpp`	22-Oct-2020	`1.9K`