use javascript heap reader to resolve frames

[Matt-Esch]

I have modified the systemtap script to output function pointer addresses only. The information associated with these addresses is pulled out of the heap by reading /proc/$pid/mem - This doesn't solve the systemtap read error issues experienced but it does offer an alternative that appears more successful despite the potential v8/crankshaft heap reshuffling

cc @danielheller @mennopruijssers @Raynos

[Raynos]

@Matt-Esch I've seen this fail in production with an EIO file error.