cmd/compile: change status of "bad iterator" panic
Execution of the loop body previously either terminated
the iteration (returned false because of a break, goto, or
return) or actually panicked. The check against abi.RF_READY
ensures that the body can no longer run and also panics.
This CL in addition transitions the loop state to abi.RF_PANIC
so that if this already badly-behaved iterator defer-recovers
this panic, then the exit check at the loop context will
catch the problem and panic there.
Previously, panics triggered by attempted execution of a
no-longer active loop would not trigger a panic at the loop
context if they were defer-recovered.
Change-Id: Ieeed2fafd0d65edb66098dc27dc9ae8c1e6bcc8c
Reviewed-on: https://go-review.googlesource.com/c/go/+/625455
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Tim King <taking@google.com>