Remove unneeded import

core/testing/runner.odin

@@ -9,7 +9,6 @@ import "core:encoding/base64"
 import "core:fmt"
 import "core:io"
 import pkg_log "core:log"
-import "core:math/rand"
 import "core:mem"
 import "core:os"
 import "core:slice"