Bug 1762812 - Remove unused `picture_cache_spatial_nodes` from tile cache builder r=gfx-reviewers,lsalzman
Bug 1762812 - Remove unused `picture_cache_spatial_nodes` from tile cache builder r=gfx-reviewers,lsalzman

Differential Revision: https://phabricator.services.mozilla.com/D142773

[ghsync] From https://hg.mozilla.org/mozilla-central/rev/89bde09d25c6bc38b76ab0bdd7cc2f6ddeaa6e0d

servo/webrender,servo/webrender,servo/webrender,servo/webrender,servo/webrender,servo/webrender