integrate py-spy

[lee218llnl]

https://github.com/benfred/py-spy#dump

[lee218llnl]

poking at this now, one issue is that we lose the ability to pause and resume since we are not attached with a debugger.

[pramodk]

@lee218llnl - I tested pyspy branch and looked at the changes. IIRC, one aspect pyspy doesn't do well is to not able to reliably profile or collect stack trace of SIGSTOP'd process. So, we have to profile the processes to generate callstack and this needs to happen in parallel in order to get an instantaneous view across all ranks/processes. Did you see something like this?