WebNN: Allow discrete operand ids for DirectML

Now the graph fusion for DirectML only supports increasing and
contiguous operand ids, but the constant folding CL[1] can provide
discrete operand ids which can cause OOB issue. To fix that, this
CL uses a map to record how many times each operand id is used as one
operation's input edge or the graph's output edge.

[1] https://chromium-review.googlesource.com/c/chromium/src/+/6040204

Bug: 380739746
Change-Id: I32e35d48e82208b15ecf656017edfcef6880659e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6047921
Reviewed-by: Austin Sullivan <asully@chromium.org>
Commit-Queue: Mingming1 Xu <mingming1.xu@intel.com>
Reviewed-by: ningxin hu <ningxin.hu@intel.com>
Reviewed-by: Alex Gough <ajgo@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1387988}