cmd/link: put .got section in __DATA_CONST segment

cmd/link: put .got section in __DATA_CONST segment

On Darwin, the .got section can be placed in a read-only segment. Only the dynamic linker should modify it at start-up time.

Other read-only sections, like .typelink and .itablink, are already placed in the __DATA_CONST segment. Do the same for the .got section.

Fixes #71416.

Cq-Include-Trybots: luci.golang.try:gotip-darwin-amd64-longtest
Change-Id: I9cd9c20da63b655fabb61d742feb086c3ef3bea7
Reviewed-on: https://go-review.googlesource.com/c/go/+/644055
Reviewed-by: Michael Pratt <mpratt@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>