Issue #3013197 by tim.plunkett: Cloning an implementation of SectionListInterface does not deep clone the Section or SectionComponent objects

(cherry picked from commit cd6c6710)

Revert "Issue #2822382 by voleger, pfrenssen, erozqba, RytoEX, borisson_, sidharthap, Jo Fitzgerald, shashikant_chauhan: Make every  property protected on classes extending BrowserTestBase and KernelTestBase"

This reverts commit 29d0958a.

Issue #2822382 by voleger, pfrenssen, erozqba, RytoEX, borisson_, sidharthap, Jo Fitzgerald, shashikant_chauhan: Make every  property protected on classes extending BrowserTestBase and KernelTestBase

(cherry picked from commit 69501f30)

Issue #2937483 by tim.plunkett, larowlan, EclipseGc, samuel.mortenson: Defining a new type of section storage relies on magic strings and hidden assumptions

Issue #2922033 by tim.plunkett, mtodor, larowlan, xjm, pameeela, EclipseGc, samuel.mortenson: Use the Layout Builder for EntityViewDisplays

Issue #2926914 by tim.plunkett, xjm, larowlan, tedbow, EclipseGc: Rewrite \Drupal\layout_builder\Section to represent the entire section, not just the block info