dtc: Extend and better test dtbs_equal utility programs (resend)

[Jon Loeliger]

> The dtbs_equal_ordered test program is used to implement a number of
> testcases.  However, the test program itself has never been
> particularly well tested.  In addition there are testcases coming in
> future for which it would be useful to have a corresponding
> "dtbs_equal_unordered" which checks for equality of device trees, not
> considering the internal ordering of elements.  Finally, for some
> tests we may want it would be useful to check trees for equality with
> the PASS case being when they are *not* equal.
> 
> This patch addresses all of the above.  A dtbs_equal_unordered is
> added, and both it and the existing dtbs_equal_ordered program now
> take a -n option to make the PASS case be where the trees are not
> equal.  A number of example trees with slight modifications from
> test_tree1 are used to verify that both these programs correctly
> identify when the tree is altered, and a dtb_reverse program is used
> to verify that the unordered version does not depend on internal
> ordering.  These new testcases for the equality testing programs are
> split out into a new test group in run_tests.sh.
> 
> dtbs_equal_unordered uses the new property iteration functions, and so
> this also acts as further testing for those functions.
> dtbs_equal_unordered will be useful for further testing the recently
> added tree-merging code and its upcoming extensions.
> 
> Signed-off-by: David Gibson <david at gibson.dropbear.id.au>

Applied.

jdl