The arm64 backend generates "TST" for "if uint32(a)&uint32(b) == 0",
which should be "TSTW".

fixes #26438

Change-Id: I7d64c30e3a840b43486bcd10eea2e3e75aaa4857
Reviewed-on: https://go-review.googlesource.com/124637
Run-TryBot: Ben Shi <powerman1st@163.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>