all: drop support for Go 1.16 and Go 1.17

src/runtime/timer.go

@@ -1,6 +1,3 @@
-//go:build go1.18
-// +build go1.18
-
 // Portions copyright 2009 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.

src/runtime/timer_go116.go

@@ -1,36 +0,0 @@
-//go:build !go1.18
-// +build !go1.18
-
-// Portions copyright 2009 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package runtime
-
-type puintptr uintptr
-
-// Package time knows the layout of this structure.
-// If this struct changes, adjust ../time/sleep.go:/runtimeTimer.
-type timer struct {
-	// If this timer is on a heap, which P's heap it is on.
-	// puintptr rather than *p to match uintptr in the versions
-	// of this struct defined in other packages.
-	pp puintptr
-
-	// Timer wakes up at when, and then at when+period, ... (period > 0 only)
-	// each time calling f(arg, now) in the timer goroutine, so f must be
-	// a well-behaved function and not block.
-	//
-	// when must be positive on an active timer.
-	when   int64
-	period int64
-	f      func(interface{}, uintptr)
-	arg    interface{}
-	seq    uintptr
-
-	// What to set the when field to in timerModifiedXX status.
-	nextwhen int64
-
-	// The status field holds one of the values below.
-	status uint32
-}