For example, `-d pctab=pctoinline` prints the PC-inline table and
inlining tree for every function.

Change-Id: Ia6b9ce4d83eed0b494318d40ffe06481ec5d58ab
Reviewed-on: https://go-review.googlesource.com/37235
Run-TryBot: David Lazar <lazard@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>