cmd/compile: fix unsafe.{SliceData,StringData} escape analysis memory corruption

cmd/compile: fix unsafe.{SliceData,StringData} escape analysis memory corruption

Fixes #57823

Change-Id: I54654d3ecb20b75afa9052c5c9db2072a86188d4
Reviewed-on: https://go-review.googlesource.com/c/go/+/461759
Reviewed-by: Cherry Mui <cherryyz@google.com>
Auto-Submit: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Reviewed-by: Keith Randall <khr@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Reviewed-by: Keith Randall <khr@google.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>