WebNN: Support axis for softmax operator
This CL adds axis parameter into the IDL and mojo definitions of softmax
operator [1]. It also updates the backends implementation to support the
new axis parameter.
In addition, the corresponding tests have also been updated.
[1] webmachinelearning/webnn#649
Bug: 338094927
Change-Id: Ib08ecbba61c27c94256953a952357eeda80241e6
Cq-Include-Trybots: luci.chromium.try:win11-blink-rel,mac14.arm64-blink-rel,mac14-blink-rel
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5495877
Reviewed-by: ningxin hu ningxin.hu@intel.com
Commit-Queue: Bin Miao bin.miao@intel.com
Reviewed-by: Austin Sullivan asully@chromium.org
Cr-Commit-Position: refs/heads/main@{#1314418}