cmd/compile: interleave devirtualization and inlining

This CL interleaves devirtualization and inlining, so that
devirtualized calls can be inlined.

Fixes #52193.

Change-Id: I681e7c55bdb90ebf6df315d334e7a58f05110d9c
Reviewed-on: https://go-review.googlesource.com/c/go/+/528321


Auto-Submit: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
TryBot-Bypass: Matthew Dempsky <mdempsky@google.com>