cmd/compile/internal/inline: rework call scoring for non-inlinable funcs
This patch fixes some problems with call site scoring, adds some new
tests, and moves more of the scoring-related code (for example, the
function "ScoreCalls") into "scoring.go". This also fixes some
problems with scoring of calls in non-inlinable functions (when new
inliner is turned on, scoring has to happen for all functions run
through the inliner, not just for inlinable functions). For such
functions, we build a table of inlinable call sites immediately prior
to scoring; the storage for this table is preserved between functions
so as to reduce allocations.
Change-Id: Ie6f691a3ad04fb7a03ab39f882a60aadaf957f6c
Reviewed-on: https://go-review.googlesource.com/c/go/+/542217 Reviewed-by: Matthew Dempsky <mdempsky@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>