[TEST ONLY] Test if any broken test to change TestStream coder context.

[shunping]

Please add a meaningful description for your change here

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[shunping]

Internal cl number: 815832173

[shunping]

A few tests failed internally:

• streaming_GroupIntoBatchesTest_testInGlobalWindowBatchSizeByteSizeFn_unified_fnapi_local
• streaming_ParDoTest_TimerTests_testEventTimeTimerCanBeReset_unified_fnapi_local
• streaming_ParDoTest_TimerTests_testEventTimeTimerOrdering_unified_fnapi_local
• streaming_ParDoTest_TimerTests_testProcessingTimeTimerCanBeReset_unified_fnapi_local
• streaming_TestStreamTest_testDiscardingMode_unified_fnapi_local
• streaming_TestStreamTest_testElementsAtAlmostPositiveInfinity_unified_fnapi_local
• streaming_TestStreamTest_testFirstElementLate_unified_fnapi_local

[shunping]

So this approach must violate some internal assumptions on coder context. Discarding.