cmd/compile: use s.temp for creating defer struct

cmd/compile: use s.temp for creating defer struct

Follow discussion in go.dev/cl/521676.

Change-Id: Ie5c0ce66b60fcbfd59385e8c2c45d431133ab53a
Reviewed-on: https://go-review.googlesource.com/c/go/+/522115
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Reviewed-by: Keith Randall <khr@google.com>
Auto-Submit: Cuong Manh Le <cuong.manhle.vn@gmail.com>
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