webnn: Separate GPU and no-GPU virtual test suites

We can't run web_tests on Linux under MSan due to the system OpenGL
libraries being uninstrumented. This is okay because the WebNN service
doesn't use the GPU on Linux (for now) so it's okay to split the
virtual test suite into a version that runs on Windows with the GPU and
a version that runs on Linux without the GPU.

Change-Id: I25b0d8facfdf5b649b8f1d0cbf9f7fa8d30ccf26
Bug: 327497661
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5332804


Commit-Queue: Reilly Grant <reillyg@chromium.org>
Reviewed-by: Ian Kilpatrick <ikilpatrick@chromium.org>
Commit-Queue: Ian Kilpatrick <ikilpatrick@chromium.org>
Auto-Submit: Reilly Grant <reillyg@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1267279}