In trying out tiered_abort in a cmake environment, I see some problems:

First, testutil_build_dir returns a path that ends with build_posix .

Second, tiered_abort/main.c has a path with "/.libs/" embedded in it, that doesn't work in a cmake world.  It looks like wt2909_checkpoint_integrity and wt3120_filesys have the same issue.  We should find a way to abstract this if we can.