[dev.typeparams] Revert "[dev.typeparams] runtime: remove unnecessary split-prevention from defer code"
This reverts CL 337651.
This causes `go test -count 1000 -run TestDeferHeapAndStack runtime`
to fail with a SIGSEGV freedefer
[https://build.golang.org/log/
c113b366cc6d51146db02a07b4d7dd931133efd5]
and possibly sometimes a GC bad pointer panic
[https://build.golang.org/log/
5b1cef7a9ad68704e9ef3ce3ad2fefca3ba86998].
Change-Id: Ie56c274b78603c81191213b302225ae19de27fb9
Reviewed-on: https://go-review.googlesource.com/c/go/+/338710
Trust: Austin Clements <austin@google.com>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>