Revert "[fuchsia] Add support for building and running CFv2 tests."

This reverts commit f96d3fec83431ec21e8fcdf658a8044b5fb2b144.

Reason for revert: Causing infra flakes as described in
https://crbug.com/1277536

Original change's description:
> [fuchsia] Add support for building and running CFv2 tests.
>
> No tests use it yet, but the plumbing largely works.
>
> - The main test() template in //testing/test.gni now allows test targets
>   to opt-in to CFv2 packaging via the `use_cfv2` boolean variable. This
>   produces a .cml manifest and generates a runner script that enables
>   CFv2 processing for test execution.
>
> - test_runner.py now takes a --component-version=2 switch to indicate
>   that a test package is a CFv2 package. This switch is added to the
>   generated runner script via the fuchsia_test_runner template when
>   `use_cfv2` is specified on a test target.
>
> - common_args.py now parses --component-version=N from the command line.
>
> - test_runner.py now handles extracting generated files from a test run
>   using two strategies based on the component version. For CFv1
>   components, files continue to be copied off of the device/emulator via
>   scp. For CFv2 components, ffx takes care of fetching the files into a
>   temporary output directory, so test_runner.py need only copy the files
>   into the caller's desired location.
>
> - run_test_package.py runs CFv2 tests via `ffx test run`, and uses the
>   new experimental structured output feature to retrieve generated files
>   from the test executable.
>
> - ffx requires networking, so fvdl_target.py now enables networking in
>   the emulator by default. net_unittests opts out of this for now.
>
> Bug: 1256502
> Change-Id: Ic9ac5d8e41274a19e06c4166fa2545525b6ec963
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3234526
> Commit-Queue: Greg Thompson <grt@chromium.org>
> Reviewed-by: Benjamin Lerman <qsr@chromium.org>
> Reviewed-by: Dirk Pranke <dpranke@google.com>
> Cr-Commit-Position: refs/heads/main@{#948883}

Bug: 1256502, 1277536
Change-Id: Ibb255532f49386cd3a55cb44e792efff4fe464d8
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3321403
Reviewed-by: Zijie He <zijiehe@google.com>
Reviewed-by: David Dorwin <ddorwin@chromium.org>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Reviewed-by: Chong Gu <chonggu@google.com>
Auto-Submit: Chong Gu <chonggu@google.com>
Reviewed-by: Dirk Pranke <dpranke@google.com>
Commit-Queue: Dirk Pranke <dpranke@google.com>
Cr-Commit-Position: refs/heads/main@{#949079}

• build/config/fuchsia/generate_runner_scripts.gni[diff]
• build/config/fuchsia/test/OWNERS[diff]
• build/config/fuchsia/test/elf_test_runner.shard.test-cml[Deleted - diff]
• build/config/fuchsia/test/minimum_capabilities.test-cml[Deleted - diff]
• build/fuchsia/common_args.py[diff]
• build/fuchsia/fvdl_target.py[diff]
• build/fuchsia/run_test_package.py[diff]
• build/fuchsia/start_emulator.py[diff]
• build/fuchsia/test_runner.py[diff]
• testing/buildbot/chromium.clang.json[diff]
• testing/buildbot/chromium.fyi.json[diff]
• testing/buildbot/chromium.linux.json[diff]
• testing/buildbot/test_suites.pyl[diff]
• testing/test.gni[diff]