Revert "cc: Use impl-side painting in LTH context lost tests."

This reverts commit fa27ef28c604c3bd343f7d8298ac3f328a9a0037.

This caused LayerTreeHostContextTestLostContextAndEvictTextures.
LoseBeforeEvict_MultiThread_DelegatingRenderer_ImplSidePaint
to crash flakily.

TBR=sohanjg@chromium.org, danakj@chromium.org
BUG=401492

Review URL: https://codereview.chromium.org/581643005

Cr-Commit-Position: refs/heads/master@{#295312}
7 files changed