[dev.ssa] cmd/compile/internal/ssa: eval defer args before setting argsize and func

[dev.ssa] cmd/compile/internal/ssa: eval defer args before setting argsize and func

Evaluating args can overwrite arg area, so we can't write argsize and func
until args are evaluated.

Fixes test/recover.go, test/recover1.go, and test/fixedbugs/issue4066.go

Change-Id: I862e4934ccdb8661431bcc3e1e93817ea834ea3f
Reviewed-on: https://go-review.googlesource.com/14405
Reviewed-by: David Chase <drchase@google.com>