Update to csi-lib-utils@v0.15.0

Manually update to csi-lib-utils@v0.15.0

It was necessary to update to kubernetes-csi/csi-test@v5.1.0 to remove dependency on cloud.google.com/go@v0.34

vendor/golang.org/x/sys/unix/syscall_solaris.go

@@ -716,20 +716,6 @@ func writelen(fd int, buf *byte, nbuf int) (n int, err error) {
 	return
 }
 
-var mapper = &mmapper{
-	active: make(map[*byte][]byte),
-	mmap:   mmap,
-	munmap: munmap,
-}
-
-func Mmap(fd int, offset int64, length int, prot int, flags int) (data []byte, err error) {
-	return mapper.Mmap(fd, offset, length, prot, flags)
-}
-
-func Munmap(b []byte) (err error) {
-	return mapper.Munmap(b)
-}
-
 // Event Ports
 
 type fileObjCookie struct {