compiler: copy receiver argument for go/defer of method call

Test case is https://golang.org/cl/302371.

Change-Id: I7b18afadee66e65b16afe840e83a5860a197b7fa
Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/302270
Trust: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>