Correct PHP 8.0 compat. false-positive

Problem/Motivation

Running a phpcs PHP 8.0 compatibility scan produces a false positive in dfp/tests/src/Functional/DisplayTagTest.php:

The behaviour of hexadecimal numeric strings was inconsistent prior to PHP 7 and support has been removed in PHP 7. Found: '0x0'

Steps to reproduce

phpcs -p . --extensions=php,module,inc,install,profile --standard=PHPCompatibility --runtime-set testVersion 8.0

Proposed resolution

Change

$edit['breakpoints[0][browser_size]'] = '0x0';

to

$edit['breakpoints[0][browser_size]'] = '0' . 'x' . '0';

Remaining tasks

N/A

User interface changes

N/A

API changes

N/A

Data model changes

N/A