cmd/compile: fix missing typecheck when rewriting abi.FuncPCABIxxx

cmd/compile: fix missing typecheck when rewriting abi.FuncPCABIxxx

Discover when running "go test -run=TestNewOSProc0 -gcflags=-d=checkptr"

Change-Id: I988da56fd3122a21673e86d7dd327ed05914ab72
Reviewed-on: https://go-review.googlesource.com/c/go/+/425040
TryBot-Result: Gopher Robot <gobot@golang.org>
Auto-Submit: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>