webnn: Immediately copy constant data
Currently, the data of ArrayBufferViews passed to the constant() method
is copied during the build() method. This does not match the spec:
https://www.w3.org/TR/webnn/#dom-mlgraphbuilder-constant
Cq-Include-Trybots: luci.chromium.try:win11-blink-rel
Bug: 348598508
Change-Id: Ief7a686324375fb2027df8a30d2c97943149bbe6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5649032
Commit-Queue: Reilly Grant reillyg@chromium.org
Reviewed-by: Reilly Grant reillyg@chromium.org
Commit-Queue: Austin Sullivan asully@chromium.org
Auto-Submit: Austin Sullivan asully@chromium.org
Cr-Commit-Position: refs/heads/main@{#1318727}