tests: don't log manifest-file in test-strip-cross.t
I'm confident that the file is there only to help produce a certain
manifest log; there is nothing special about the file's filelog
itself. (And there already is a `hg debugindex --manifest` call higher
up in the file that shows the crossed linkrevs.)
Differential Revision: https://phab.mercurial-scm.org/D6791
#require emacs
$ emacs -q -no-site-file -batch -l $TESTDIR/../contrib/hg-test-mode.el \
> -f ert-run-tests-batch-and-exit
Running 1 tests (*) (glob)
passed 1/1 hg-test-mode--compilation-mode-support
Ran 1 tests, 1 results as expected (*) (glob)