simpleperf: Improve Callgraph.

1. Reduce columns used by callgraph by reducing spaces between
entries from 11 to 4. This helps to show more entries in the limited screen width.
2. Add [hit-in-function] line for each entry, so we know the percentage
of samples hit in the function and samples hit in the children functions.
3. Add --kallsyms option for report command.

After all, The callgraph is changed like below.
Before change:
 |--99.08%-- java.lang.Thread.run
 |           void com.example.cyb.tappydefender.TDView.run()
 |           |
 |           |           |--95.63%-- void com.example.cyb.tappydefender.TDView.draw()

After change:
 |--98.85%-- java.lang.Thread.run
 |           void com.example.cyb.tappydefender.TDView.run()
 |    |--0.09%-- [hit in function]
 |    |
 |    |--95.54%-- void com.example.cyb.tappydefender.TDView.draw()

Bug: http://b/33356538
Test: run simpleperf_unit_test.
Test: run simpleperf report -g manually.
Change-Id: Ifc1846d4ee7469cadbcc727cae6bf59552d919d5
5 files changed