slices: make Insert panic if index is out of range and there are no values
Fixes #63913
Change-Id: I514190b104a2c4bd5a6b0d96659b52904185e91f
GitHub-Last-Rev:
90e7195193b8e50009fc0d9dcbda953b1ec509b4
GitHub-Pull-Request: golang/go#63965
Reviewed-on: https://go-review.googlesource.com/c/go/+/540155
Reviewed-by: Keith Randall <khr@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Heschi Kreinick <heschi@google.com>
Run-TryBot: Jes Cok <xigua67damn@gmail.com>
Reviewed-by: Keith Randall <khr@google.com>