cmd/internal/obj: remove LSym.RefIdx

LSym.RefIdx was for the old object files. I should have deleted
it when I deleted old object file code.

Change-Id: I8294f43a1e7ba45b1d75e84cc83cbaf2cb32f025
Reviewed-on: https://go-review.googlesource.com/c/go/+/262077
Trust: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Jeremy Faller <jeremy@golang.org>

src/cmd/internal/obj/link.go

@@ -395,7 +395,6 @@ type LSym struct {
 	Type objabi.SymKind
 	Attribute
 
-	RefIdx int // Index of this symbol in the symbol reference list.
 	Size   int64
 	Gotype *LSym
 	P      []byte
@@ -405,7 +404,7 @@ type LSym struct {
 
 	Pkg    string
 	PkgIdx int32
-	SymIdx int32 // TODO: replace RefIdx
+	SymIdx int32
 }
 
 // A FuncInfo contains extra fields for STEXT symbols.

src/cmd/internal/obj/sizeof_test.go

@@ -21,7 +21,7 @@ func TestSizeof(t *testing.T) {
 		_64bit uintptr     // size on 64bit platforms
 	}{
 		{Addr{}, 32, 48},
-		{LSym{}, 76, 128},
+		{LSym{}, 72, 120},
 		{Prog{}, 132, 200},
 	}