Remove deprecated WriteTree from tests

These tests doesn't need to use WriteTree anymore.  There are
other means of creating tree objects in the repository that aren't
deprecated, so use those instead.

Change-Id: I89cd8ab54c66964a5fddc0a045f1c0f1c7c49055
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
2 files changed