time: add wasm architecture

This commit adds the wasm architecture to the time package.

Updates #18892

Change-Id: I86841e096894eacf7f972add9a532491e4d00014
Reviewed-on: https://go-review.googlesource.com/106997
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

src/syscall/time_js_wasm.s

+// Copyright 2018 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.
+
+#include "textflag.h"
+
+TEXT ·startTimer(SB),NOSPLIT,$0
+	JMP time·startTimer(SB)
+
+TEXT ·stopTimer(SB),NOSPLIT,$0
+	JMP time·stopTimer(SB)

src/syscall/timestruct.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build darwin dragonfly freebsd linux nacl netbsd openbsd solaris
+// +build darwin dragonfly freebsd js,wasm linux nacl netbsd openbsd solaris
 
 package syscall
 

src/time/sys_unix.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build darwin dragonfly freebsd linux nacl netbsd openbsd solaris
+// +build darwin dragonfly freebsd js,wasm linux nacl netbsd openbsd solaris
 
 package time
 

src/time/zoneinfo_unix.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build darwin,386 darwin,amd64 dragonfly freebsd linux,!android nacl netbsd openbsd solaris
+// +build darwin,386 darwin,amd64 dragonfly freebsd js,wasm linux,!android nacl netbsd openbsd solaris
 
 // Parse "zoneinfo" time zone file.
 // This is a fairly standard file format used on OS X, Linux, BSD, Sun, and others.