types/views: optimize slices contains under some conditions (#11449)

In control there are conditions where the leaf functions are not being
optimized away (i.e. At is not inlined), resulting in undesirable time
spent copying during SliceContains. This optimization is likely
irrelevant to simpler code or smaller structures.

Updates #optimization

Signed-off-by: James Tucker <james@tailscale.com>

types/views/views.go

@@ -274,8 +274,8 @@ func (v Slice[T]) IndexFunc(f func(T) bool) int {
 //
 // As it runs in O(n) time, use with care.
 func (v Slice[T]) ContainsFunc(f func(T) bool) bool {
-	for i := 0; i < v.Len(); i++ {
-		if f(v.At(i)) {
+	for _, x := range v.ж {
+		if f(x) {
 			return true
 		}
 	}
@@ -286,8 +286,8 @@ func (v Slice[T]) ContainsFunc(f func(T) bool) bool {
 //
 // As it runs in O(n) time, use with care.
 func SliceContains[T comparable](v Slice[T], e T) bool {
-	for i := 0; i < v.Len(); i++ {
-		if v.At(i) == e {
+	for _, x := range v.ж {
+		if x == e {
 			return true
 		}
 	}
@@ -296,8 +296,8 @@ func SliceContains[T comparable](v Slice[T], e T) bool {
 
 // SliceContainsFunc reports whether f reports true for any element in v.
 func SliceContainsFunc[T any](v Slice[T], f func(T) bool) bool {
-	for i := 0; i < v.Len(); i++ {
-		if f(v.At(i)) {
+	for _, x := range v.ж {
+		if f(x) {
 			return true
 		}
 	}