cmd/link/internal/ld: fix c-archive mach-o compatibility

These workarounds predate proper DWARF support
and are no longer necessary.

Before this patch, running `/usr/bin/symbols go.o`
using the object in the c-archive would fail, causing
App Store rejections.

Fixes #31022 #28997

Change-Id: I6a210b6369c13038777c6e21e874e81afcb50c2f
Reviewed-on: https://go-review.googlesource.com/c/go/+/170377


Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>