Fix duplicate method name in test_project.py

flake8 reports:

  F811 redefinition of unused 'test_src_block_dir' from line 259

which is caused by having two methods with the same name. Rename
them both to better desribe their purpose.

Change-Id: If7612a42001776d71bb1a6a80fc631d3d262e6ce
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/254449
Reviewed-by: Mike Frysinger <vapier@google.com>
Tested-by: David Pursehouse <dpursehouse@collab.net>