MLBEDSW-4157: Add RESIZE_NEAREST_NEIGHBOR support

 - Changed ResizeBilinear to support ResizeNearestNeighbor as well for
1x1 IFM, IFM equal OFM, and non-align corners
 - Added support for ResizeNearestNeighbor with align corners by
converting to a DepthwiseConv
 - Updated supported operator unit tests
 - Added is_resize() helper function and some associated refactoring

Signed-off-by: Tim Hall <tim.hall@arm.com>
Change-Id: Id5bdf2a25e8aa6a4f28b7236250abf768141ce37
diff --git a/ethosu/vela/register_command_stream_generator.py b/ethosu/vela/register_command_stream_generator.py
index 12a36ca..a8d1ddf 100644
--- a/ethosu/vela/register_command_stream_generator.py
+++ b/ethosu/vela/register_command_stream_generator.py
@@ -706,7 +706,7 @@
             scale = explicit_scaling.multiplier[0]
             shift = explicit_scaling.shift[0]
         else:
-            # for ResizeBilinear operations with rescale
+            # for ResizeBilinear/NearestNeighbor operations with rescale
             rescale = pool_op.rescale
             rescale_bits = len(bin(round_up_to_int(rescale))) - 2 + 1
             scale, shift = scaling.quantise_pooling_scale(kernel.height * kernel.width, rescale_bits)