Update asserts jsdoc to put statements on separate lines.
Update asserts jsdoc to put statements on separate lines.

This formatting is stable even after running the auto-formatters.

RELNOTES: n/a

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=236244945

google/closure-library,lucidsoftware/closure-library,google/closure-library,google/closure-library,lucidsoftware/closure-library,lucidsoftware/closure-library,lucidsoftware/closure-library,google/closure-library,google/closure-library