bytes: annotate assembly functions with //go:noescape

R=golang-dev, agl, bradfitz, rsc
CC=golang-dev
https://golang.org/cl/7299064

src/pkg/bytes/bytes.go

@@ -37,10 +37,6 @@ func Compare(a, b []byte) int {
 	return 0
 }
 
-// Equal returns a boolean reporting whether a == b.
-// A nil argument is equivalent to an empty slice.
-func Equal(a, b []byte) bool
-
 func equalPortable(a, b []byte) bool {
 	if len(a) != len(b) {
 		return false

src/pkg/bytes/bytes_decl.go

@@ -4,5 +4,13 @@
 
 package bytes
 
+//go:noescape
+
 // IndexByte returns the index of the first instance of c in s, or -1 if c is not present in s.
 func IndexByte(s []byte, c byte) int // asm_$GOARCH.s
+
+//go:noescape
+
+// Equal returns a boolean reporting whether a == b.
+// A nil argument is equivalent to an empty slice.
+func Equal(a, b []byte) bool // asm_$GOARCH.s