Intermittent failure of post-early-return AuTest

[masaori335]

The post-early-return AuTest seems flaky. The second build was passed without any change.

 Test: post-early-return: Failed
    File: post-early-return.test.py
    Directory: /home/jenkins/workspace/Github_Builds/autest/src/tests/gold_tests/post
...
   Process: ts: Failed
...
     file /tmp/sandbox/post-early-return/ts/log/diags.log : Diags log file diags.log should not contain errors - Failed
        Reason: Contents of /tmp/sandbox/post-early-return/ts/log/diags.log contains expression: "ERROR:"
           Details:
             [Aug  9 00:10:43.935] [ET_NET 1] ERROR: HTTP/2 stream error code=0x02 client_ip=127.0.0.1 session_id=4 stream_id=1  : 38
             [Aug  9 00:10:43.935] [ET_NET 1] ERROR: HTTP/2 stream error code=0x05 client_ip=127.0.0.1 session_id=4 stream_id=1 recv data stream closed : 39
             [Aug  9 00:10:43.935] [ET_NET 1] ERROR: HTTP/2 stream error code=0x05 client_ip=127.0.0.1 session_id=4 stream_id=1 recv data stream closed : 40
             [Aug  9 00:10:43.935] [ET_NET 1] ERROR: HTTP/2 stream error code=0x05 client_ip=127.0.0.1 session_id=4 stream_id=1 recv data stream closed : 41
             [Aug  9 00:10:43.935] [ET_NET 1] ERROR: HTTP/2 stream error code=0x05 client_ip=127.0.0.1 session_id=4 stream_id=1 recv data stream closed : 42
...
   Run: http2 Post with large body, small window and early return: Failed
     Test : Checking that True == _isRunningAfter - Passed
        Reason: Returned Value: True == _isRunningAfter
     Starting TestRun 2-tr : No Issues found - Passed
        Reason: Started!
     Process: Default: Failed
       Test : Checking that ReturnCode == 0 - Failed
          Reason: Returned Value 92 != 0
       Time-Out : Process finishes within expected time - Passed
          Reason: Returned value: 1.0055491924285889 < 600.0
       file /tmp/sandbox/post-early-return/_output/2-tr-Default/stream.all.txt : Receive the early response - Passed
          Reason: Contents of /tmp/sandbox/post-early-return/_output/2-tr-Default/stream.all.txt contained expression

https://ci.trafficserver.apache.org/job/Github_Builds/job/autest/1334/console