Support for displaying low-level perf profile data produced by ll_prof.py

[mraleph]

It would be really cool to be able to upload and display per-instruction and per-function profile data along with the IR/disassembly.

Here are two example files, one with disassembly, one without produced by V8's ll_prof.py script using a modified versions of Dart VM.

https://code.google.com/p/irhydra/issues/detail?id=20

[mraleph]

The mode used to work, but is disabled in polymerized branch. Must reenable it.