cmd/{5,6,8,9}g, cmd/internal/gc: use bools for is* and okfor*

No functional changes.

This diff was generated as follows:

* Manually edit cmd/internal/gc/go.go to update types and group variables.
* Manually edit initialization in cmd/internal/gc/align.go--localized s/1/true.
* Manually fix the handling of sign in cmd/internal/gc/walk.go in func bounded (near line 4000).
* Manually update go.y and regenerate y.go.
* Run gofmt -r many times to do the rest, using https://gist.github.com/josharian/0f61dbb2dff81f938e70.

toolstash -cmp on the stdlib comes back green.

Change-Id: I19766ed551714e51b325133e7138818d117b3a9a
Reviewed-on: https://go-review.googlesource.com/6530
Reviewed-by: Russ Cox <rsc@golang.org>
diff --git a/src/cmd/internal/gc/reflect.go b/src/cmd/internal/gc/reflect.go
index 6059e35..732dd36 100644
--- a/src/cmd/internal/gc/reflect.go
+++ b/src/cmd/internal/gc/reflect.go
@@ -358,10 +358,10 @@
 		// method does not apply.
 		this = getthisx(f.Type).Type.Type
 
-		if Isptr[this.Etype] != 0 && this.Type == t {
+		if Isptr[this.Etype] && this.Type == t {
 			continue
 		}
-		if Isptr[this.Etype] != 0 && Isptr[t.Etype] == 0 && f.Embedded != 2 && !isifacemethod(f.Type) {
+		if Isptr[this.Etype] && !Isptr[t.Etype] && f.Embedded != 2 && !isifacemethod(f.Type) {
 			continue
 		}
 
@@ -693,7 +693,7 @@
 	}
 
 	var sptr *Sym
-	if t.Sym != nil && Isptr[t.Etype] == 0 {
+	if t.Sym != nil && !Isptr[t.Etype] {
 		sptr = dtypesym(Ptrto(t))
 	} else {
 		sptr = weaktypesym(Ptrto(t))
@@ -868,7 +868,7 @@
 }
 
 func typenamesym(t *Type) *Sym {
-	if t == nil || (Isptr[t.Etype] != 0 && t.Type == nil) || isideal(t) {
+	if t == nil || (Isptr[t.Etype] && t.Type == nil) || isideal(t) {
 		Fatal("typename %v", Tconv(t, 0))
 	}
 	s := typesym(t)
@@ -987,7 +987,7 @@
 	// emit the type structures for int, float, etc.
 	tbase := t
 
-	if Isptr[t.Etype] != 0 && t.Sym == nil && t.Type.Sym != nil {
+	if Isptr[t.Etype] && t.Sym == nil && t.Type.Sym != nil {
 		tbase = t.Type
 	}
 	dupok := 0
@@ -1003,7 +1003,7 @@
 	if tbase.Sym != nil && tbase.Local == 0 {
 		return s
 	}
-	if isforw[tbase.Etype] != 0 {
+	if isforw[tbase.Etype] {
 		return s
 	}