Disasm and weblist don't work on inline functions.

### What version of pprof are you using?
pprof_20170918_00_RC00

### What operating system and processor architecture are you using?
Linux/Intel

### What did you do?

"list " works, but weblist fails with "No source information" and disasm just prints the total.

It appears that pprof knows that my function is inline (according to "top" listing), so could we at least get a better error message?

Thanks a lot!

(pprof) top
Showing nodes accounting for 38.68s, 99.82% of 38.75s total
Dropped 12 nodes (cum <= 0.19s)
Showing top 10 nodes out of 12
flat flat% sum% cum cum%
[...]
8.50s 21.94% 99.28% 23.02s 59.41% <...function...> (inline)
[...]
(pprof) weblist <...function...>
No source information for <...function...>
(pprof) disasm <...function...>
Total: 38.75s
(pprof)