GHCJS issue at high yield rates on an async channel

[harendra-kumar]

Running the maxrate test results in a crash at yield rates of 10000 or above.

uncaught exception in Haskell thread: TypeError: Cannot read property 'd1' of undefined
TypeError: Cannot read property 'd1' of undefined
    at h$$bky (/vol/hosts/cueball/workspace/packages/streamly/dist-newstyle/build/x86_64-linux/ghcjs-8.6.0.1/streamly-0.6.0/build/maxrate/maxrate.jsexe/all.js:116253:12)
    at h$runThreadSlice (/vol/hosts/cueball/workspace/packages/streamly/dist-newstyle/build/x86_64-linux/ghcjs-8.6.0.1/streamly-0.6.0/build/maxrate/maxrate.jsexe/all.js:8272:11)
    at h$runThreadSliceCatch (/vol/hosts/cueball/workspace/packages/streamly/dist-newstyle/build/x86_64-linux/ghcjs-8.6.0.1/streamly-0.6.0/build/maxrate/maxrate.jsexe/all.js:8239:12)
    at Immediate.h$mainLoop [as _callback] (/vol/hosts/cueball/workspace/packages/streamly/dist-newstyle/build/x86_64-linux/ghcjs-8.6.0.1/streamly-0.6.0/build/maxrate/maxrate.jsexe/all.js:8232:9)
    at runCallback (timers.js:672:20)
    at tryOnImmediate (timers.js:645:5)
    at processImmediate [as _immediateCallback] (timers.js:617:5)
  asyncly rate: 10000.0, consumer latency: 0, producer latency: (0.0,0.0) FAILED [1]

Failures:

  test/MaxRate.hs:35:5: 
  1) asyncly no consumer delay no producer delay asyncly rate: 10000.0, consumer latency: 0, producer latency: (0.0,0.0)
       uncaught exception: BlockedIndefinitelyOnMVar
       thread blocked indefinitely in an MVar operation

  To rerun use: --match "/asyncly no consumer delay no producer delay/asyncly rate: 10000.0, consumer latency: 0, producer latency: (0.0,0.0)/"

See GHCJS issue ghcjs/ghcjs#635