ipcz: Parameterize tests over feature sets

This change introduces an additional layer of parameterization for
ipcz multinode unit tests, allowing tests to provide coverage over
multiple distinct feature sets in the same test suite execution so
that new features can have coverage while under development.

Generated test names now follow the convention:

  TestSuite.TestName/Driver_FeatureSet

Two initial feature sets are defined: "Default" and "MemV2", the
latter of which enables (currently no-op) IPCZ_FEATURE_MEM_V2.

Bug: 332719403
Change-Id: Ia59ae2c0d9c6afeeb3f56e01209551ce487de6ef
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5444219
Reviewed-by: Alex Gough <ajgo@chromium.org>
Commit-Queue: Ken Rockot <rockot@google.com>
Cr-Commit-Position: refs/heads/main@{#1287394}