test-hgweb-annotate-whitespace: make test compatible with chg D946 fixed a bunch of tests which had the same root cause. Please see that for details. This seems to be one of the newer tests which fails because of the same reason. Test Plan: Ran the test 'test-hgweb-annotate-whitespace.t' with and without the '--chg' option. Differential Revision: https://phab.mercurial-scm.org/D1124