This can be done in parallel with any other PM-1546 work.

Create a new whatthefailure.js javascript file (class) in the shell. For now this will just have a single static method called WTF.areOtherMongosDoing(opts) (name subject to change). This will shell out to the existing hang_analyzer.py script via the runProgram shell built-in.

The opts parameter has the following fields:

1. pids optional array of pids to pass into hang-analyzer. If not specified will use the pids of child and/or peer mongo processes obtained via TestData or shell built-ins (both added in other tickets)
2. args optional array of strings - additional set of args to pass to hang-analyzer. If not specified will use reasonable defaults (probably just empty). This is a "private" parameter (not documented or required to be backward-compatible) because most users should never need to use/see/set it.