Consolidate reference_file and is_test_reference into a single param

[chromium-wpt-export-bot]

The Canvas WPT test generator was using two variables to control how a
test file links to it's reference file: 'reference_file' and
'is_test_reference'. In the context of documenting all parameters,
having to explain why we have two different parameters to do this one
thing is awkward. The logic and documentation will be simpler by using a
single 'reference_file_link' parameter.

Bug: 393561071
Change-Id: Id4523455f72ceb94684799cd672d11d87c106653
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6219871
Reviewed-by: Andres Ricardo Perez <[email protected]>
Commit-Queue: Jean-Philippe Gravel <[email protected]>
Cr-Commit-Position: refs/heads/main@{#1423298}

[wpt-pr-bot]

The review process for this patch is being conducted in the Chromium project.

[jonathan-j-lee]

+ ./wpt update-built
ERROR: Could not install packages due to an EnvironmentError: ("Connection broken: ConnectionResetError(104, 'Connection reset by peer')", ConnectionResetError(104, 'Connection reset by peer'))

CRITICAL:tools.wpt.utils:('/home/test/web-platform-tests/_venv3/bin/pip3', 'install', '--prefer-binary', '-r', '/home/test/web-platform-tests/tools/ci/requirements_build.txt') exited with return code 1
CRITICAL:tools.wpt.utils:b'Collecting cairocffi==1.7.0\n  Downloading cairocffi-1.7.0-py3-none-any.whl (75 kB)\n'
Traceback (most recent call last):
  File "./wpt", line 10, in <module>
    wpt.main()
  File "/home/test/web-platform-tests/tools/wpt/wpt.py", line 210, in main
    venv = setup_virtualenv(main_args.venv, main_args.skip_venv_setup, props)
  File "/home/test/web-platform-tests/tools/wpt/wpt.py", line 169, in setup_virtualenv
    venv.install_requirements(*props.get("requirements", []))
  File "/home/test/web-platform-tests/tools/wpt/virtualenv.py", line 180, in install_requirements
    call(*cmd)
  File "/home/test/web-platform-tests/tools/wpt/utils.py", line 27, in call
    return subprocess.check_output(args).decode('utf8')
  File "/usr/lib/python3.8/subprocess.py", line 415, in check_output
    return run(*popenargs, stdout=PIPE, timeout=timeout, check=True,
  File "/usr/lib/python3.8/subprocess.py", line 516, in run
    raise CalledProcessError(retcode, process.args,
subprocess.CalledProcessError: Command '('/home/test/web-platform-tests/_venv3/bin/pip3', 'install', '--prefer-binary', '-r', '/home/test/web-platform-tests/tools/ci/requirements_build.txt')' returned non-zero exit status 1.

Trying again...