cmd/compile: use newnamel in typenamesym

The node in typenamesym requires neither
a position nor a curfn.

Passes toolstash-check.

Updates #15756

Change-Id: I6d39a8961e5578fe5924aaceb29045b6de2699df
Reviewed-on: https://go-review.googlesource.com/39194
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

src/cmd/compile/internal/gc/reflect.go

@@ -7,6 +7,7 @@ package gc
 import (
 	"cmd/internal/gcprog"
 	"cmd/internal/obj"
+	"cmd/internal/src"
 	"fmt"
 	"os"
 	"sort"
@@ -936,7 +937,7 @@ func typenamesym(t *Type) *Sym {
 	}
 	s := typesym(t)
 	if s.Def == nil {
-		n := newname(s)
+		n := newnamel(src.NoXPos, s)
 		n.Type = Types[TUINT8]
 		n.Class = PEXTERN
 		n.Typecheck = 1