Replace debug() statements in Views

Follow-up #2853359: Runtime debug statement in Views now prints out object:

@Lendude:

Printing debug information on a live system feels wrong. Looks like Views is the only place in core where this currently happens outside of tests, so should we maybe take them all out?
\Drupal\views\Plugin\views\field\FieldPluginBase::addAdditionalFields
\Drupal\views\Plugin\views\style\Opml::render
\Drupal\views\Plugin\views\style\Rss::render
\Drupal\views\Plugin\views\style\StylePluginBase::render

@dawehner

This code is probably coming from Drupal 6, where exceptions weren't really a thing, given views was compatible with php 4.

@Lendude

IMO debug statements should not live in core code and as @dawehner pointed out in #11, this is probably a leftover from D6/PHP4 times, so it could do with an update to more current best practice.

Problem/Motivation

debug() has worked its way (for live in core code), and is no longer the best practice.

We have also few other problem with debug:

• #2844732: Drupal treats all user-level PHP notices as debug messages
• #2692867: debug() statement causes caches to be ignored, hence debug() in a failing test suddenly causes it to pass
• #2552163: Do not use FormattableMarkup in exceptions, trigger_error, and debug (the second pass)

Proposed resolution

• Smooth replacement through the trigger_error.
• Replace on other tools, like #2096815: Replace debug() output with Krumo
• Repair, like #2795567: Use Symfony's VarDumper for easier test debugging with dump()

Remaining tasks

User interface changes

API changes

Data model changes