cmd/compile: use internal/buildcfg for checking newinliner enable

internal/goexperiment reports what GOEXPERIMENT the compiler itself was
compiled with, not what experiment to use for the object code that the
compiler is compiling.

Fixes #64189

Change-Id: I892d78611f8c76376032fd7459e755380afafac6
Reviewed-on: https://go-review.googlesource.com/c/go/+/542995
Auto-Submit: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>

src/cmd/compile/internal/inline/inlheur/analyze.go

@@ -10,7 +10,7 @@ import (
 	"cmd/compile/internal/types"
 	"encoding/json"
 	"fmt"
-	"internal/goexperiment"
+	"internal/buildcfg"
 	"io"
 	"os"
 	"path/filepath"
@@ -213,7 +213,7 @@ func fnFileLine(fn *ir.Func) (string, uint) {
 }
 
 func Enabled() bool {
-	return goexperiment.NewInliner || UnitTesting()
+	return buildcfg.Experiment.NewInliner || UnitTesting()
 }
 
 func UnitTesting() bool {

src/cmd/compile/internal/noder/linker.go

@@ -6,7 +6,6 @@ package noder
 
 import (
 	"internal/buildcfg"
-	"internal/goexperiment"
 	"internal/pkgbits"
 	"io"
 
@@ -297,7 +296,7 @@ func (l *linker) relocFuncExt(w *pkgbits.Encoder, name *ir.Name) {
 	if inl := name.Func.Inl; w.Bool(inl != nil) {
 		w.Len(int(inl.Cost))
 		w.Bool(inl.CanDelayResults)
-		if goexperiment.NewInliner {
+		if buildcfg.Experiment.NewInliner {
 			w.String(inl.Properties)
 		}
 	}

src/cmd/compile/internal/noder/reader.go

@@ -8,7 +8,6 @@ import (
 	"fmt"
 	"go/constant"
 	"internal/buildcfg"
-	"internal/goexperiment"
 	"internal/pkgbits"
 	"path/filepath"
 	"strings"
@@ -1103,7 +1102,7 @@ func (r *reader) funcExt(name *ir.Name, method *types.Sym) {
 				Cost:            int32(r.Len()),
 				CanDelayResults: r.Bool(),
 			}
-			if goexperiment.NewInliner {
+			if buildcfg.Experiment.NewInliner {
 				fn.Inl.Properties = r.String()
 			}
 		}