webnn: add IDL and mojo definition of gelu operator
This CL also adds validation tests in WPTs and a unit test
WebNNGraphImplTest.GeluTest.
Bug: 40206287
Change-Id: Ia197fa637e036e73c4e7d5e832685364633c0384
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5470161
Commit-Queue: Shiyi Zou shiyi.zou@intel.com
Reviewed-by: Alex Gough ajgo@chromium.org
Reviewed-by: ningxin hu ningxin.hu@intel.com
Auto-Submit: Shiyi Zou shiyi.zou@intel.com
Reviewed-by: Austin Sullivan asully@chromium.org
Cr-Commit-Position: refs/heads/main@{#1292836}