Automated g4 rollforward of changelist 235783448.
Automated g4 rollforward of changelist 235783448.

*** Reason for rollforward ***

Fixed all tests: http://test/OCL:236693555:BASE:236665350:1551753206810:91680c35
Rerun after final fix CL: http://test/OCL:236693555:BASE:236855821:1551804523497:8d20b76b

*** Original change description ***

RELNOTES: Fix return type annotation for assertThrows().

This allows test code to assert about its result's properties.

***

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=236876162

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