Make ResourceProfiler more robust (#2286)
Make ResourceProfiler more robust (#2286)

Previously processes could be dropped after a tracking loop was started,
which may lead to an exception due to trying to get memory/cpu info from
a dead process. This PR fixes this to handle dead processes whenever
information is recorded.
dask/dask,mrocklin/dask,blaze/dask,mraspaud/dask,jcrist/dask,ContinuumIO/dask,dask/dask,mrocklin/dask,jcrist/dask,jakirkham/dask,mraspaud/dask,ContinuumIO/dask,blaze/dask,jakirkham/dask