reflect: update to Go 1.22 semantics

The IsZero function was changed slightly in Go 1.22, so we'll need to
update it.

While this could in theory break existing programs that rely on the old
behavior, they'd also break with the imminent Go 1.22 release so I don't
think this is a real problem.

src/reflect/value.go

@@ -124,10 +124,9 @@ func (v Value) IsZero() bool {
 	case Uint, Uint8, Uint16, Uint32, Uint64, Uintptr:
 		return v.Uint() == 0
 	case Float32, Float64:
-		return math.Float64bits(v.Float()) == 0
+		return v.Float() == 0
 	case Complex64, Complex128:
-		c := v.Complex()
-		return math.Float64bits(real(c)) == 0 && math.Float64bits(imag(c)) == 0
+		return v.Complex() == 0
 	case Array:
 		for i := 0; i < v.Len(); i++ {
 			if !v.Index(i).IsZero() {
@@ -141,7 +140,7 @@ func (v Value) IsZero() bool {
 		return v.Len() == 0
 	case Struct:
 		for i := 0; i < v.NumField(); i++ {
-			if !v.Field(i).IsZero() {
+			if !v.Field(i).IsZero() && v.Type().Field(i).Name != "_" {
 				return false
 			}
 		}