Expose a profile to pprof CLI

[concavelenz]

It would be useful to be able to take existing .cpuprofile files an be able to convert them to pprofs

[ofrobots]

Context: while this module supports online gathering of V8 cpuprofiles and then converting them to profile.proto.gz, it would be nice to have a standalone CLI that can convert V8 cpuprofile files to profile.proto so that one can use pprof to view them.