test: add error tests for Glob with links
test: add error tests for Glob with links

Change-Id: I4b0ada3109ada2e725439a7ad4976c69dccd5272
Reviewed-on: https://upspin-review.googlesource.com/4963
Reviewed-by: Rob Pike <4dc7c9ec434ed06502767136789763ec11d2c4b7@google.com>

upspin/upspin,upspin/upspin