[GHC] #16100: T11627a fails sometimes on CI

[GHC]

#16100: T11627a fails sometimes on CI
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        Reporter:  mpickering        |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.6.3
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by RyanGlScott):

 `heapprof001` also occasionally fails with the same panic ([https://ghc-
 gitlab.s3.amazonaws.com/6b/86/6b86b273ff34fce19d6b804eff5a3f5747ada4eaa22f1d49c01e52ddb7875b4b/2019_01_17/12575/17445/job.log
 ?response-content-type=text/plain%3B%20charset%3Dutf-8&response-content-
 disposition=inline&X-Amz-Expires=600&X-Amz-Date=20190117T113941Z&X-Amz-
 Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIAI3NPPHETCY4XXTOA/20190117
 /us-east-1/s3/aws4_request&X-Amz-SignedHeaders=host&X-Amz-
 Signature=383c0778b825e04099591919b5cb44dae3662cb42cd69b125cf3def62e142e10
 example] from a `validate-x86_64-linux-fedora27` configuration):

 {{{
 Wrong exit code for heapprof001(prof_hc_hb)(expected 0 , actual 134 )
 Stdout ( heapprof001 ):
 a <=
 a <=
 a <=
 a <=
 a <=
 a <=
 a <=
 Stderr ( heapprof001 ):
 heapprof001: internal error: LDV_recordDead: Failed to find counter for
 closure 0x42000af050
     (GHC version 8.7.20190115 for x86_64_unknown_linux)
     Please report this as a GHC bug:
 https://www.haskell.org/ghc/reportabug
 *** unexpected failure for heapprof001(prof_hc_hb)}}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/16100#comment:2>
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