webnn: Implement buildGraphAndCompute and add two operators' tests
This cl updates the buildGraphAndCompute method to support subgraphs
with multiple operators. The output precision for such subgraphs is the
sum of the individual operators’ precisions. Basic tests for both
operators have been added.
Bug: 333756077
Change-Id: I959d307127503e3a81c82aba91351e97d2edd8dd
Cq-Include-Trybots: luci.chromium.try:mac14-blink-rel,mac14.arm64-blink-rel,win11-blink-rel
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5799843
Reviewed-by: ningxin hu ningxin.hu@intel.com
Reviewed-by: Austin Sullivan asully@chromium.org
Reviewed-by: David Baron dbaron@chromium.org
Commit-Queue: Shanxing Mei shanxing.mei@intel.com
Cr-Commit-Position: refs/heads/main@{#1357962}