18026 Roll fuchsia/sdk/core/linux-amd64 from NeQ_8… to sKCYL… (cla: yes, waiting for tree to go green)

18029 soften shadows even more; fix shadow alpha (cla: yes)

18032 [web] Use correct shell operator to compare file limits (cla: yes, platform-web)

18033 Revert all build changes made to test the Dart NNBD unfork CL. (cla: yes)

18034 [web] First batch of unit tests for line breaker (cla: yes, platform-web)

18035 [web] remove linux-chrome unit tests from cirrus CI (cla: yes)