67468 Remove Cirrus support for Gold (a: tests, cla: yes, framework, team, team: infra, will affect goldens)

67476 fix build analysis errors (cla: yes, f: cupertino, framework)

67477 Migrate some material tests to nnbd (cla: yes, f: material design, framework)

67482 Migrate More Material Tests (cla: yes, f: material design, framework, waiting for tree to go green)

67525 unnecessary null comparison (a: tests, cla: yes, f: material design, framework, waiting for tree to go green)

67545 Reland removal of examples/catalog (a: accessibility, cla: yes, d: examples, f: material design, framework, team, waiting for tree to go green)