cmd/internal/gc: convert yet more Node fields to bools

Convert Embedded, Method, and Colas to bools.

I believe that this is the last of the Node fields
that can be trivially converted to bools.

No functional changes. Passes toolstash -cmp.

Change-Id: I81962ee47866596341fc60d24d6959c20cd7fc1c
Reviewed-on: https://go-review.googlesource.com/8440
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
diff --git a/src/cmd/internal/gc/dcl.go b/src/cmd/internal/gc/dcl.go
index c8375dd..786b7b2 100644
--- a/src/cmd/internal/gc/dcl.go
+++ b/src/cmd/internal/gc/dcl.go
@@ -367,7 +367,7 @@
 	n := Nod(ONAME, nil, nil)
 	n.Sym = s
 	n.Type = nil
-	n.Addable = 1
+	n.Addable = true
 	n.Ullman = 1
 	n.Xoffset = 0
 	return n
@@ -438,7 +438,7 @@
 			c.Class = PPARAMREF
 			c.Isddd = n.Isddd
 			c.Defn = n
-			c.Addable = 0
+			c.Addable = false
 			c.Ullman = 2
 			c.Funcdepth = Funcdepth
 			c.Outer = n.Closure
@@ -521,7 +521,7 @@
 	as := Nod(OAS2, nil, nil)
 	as.List = left
 	as.Rlist = right
-	as.Colas = 1
+	as.Colas = true
 	as.Lineno = lno
 	colasdefn(left, as)