cmd/compile: remove bug workarounds in prove's loop inversion
I wrote theses checks because I got bad panics on some innocent functions,
turns out I was working around #63955 but I was not aware of that at the time.
The proper fix was included in CL 539977 this is now doing nothing.
Change-Id: I89329329933527b6f3cb817dc1e039a38f58da9a
Reviewed-on: https://go-review.googlesource.com/c/go/+/560975 Reviewed-by: Keith Randall <khr@golang.org> Reviewed-by: Keith Randall <khr@google.com>
Auto-Submit: Keith Randall <khr@golang.org> Reviewed-by: Michael Knyszek <mknyszek@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>