cmd/link: do not add label symbols for DWARF on Windows/ARM64

cmd/link: do not add label symbols for DWARF on Windows/ARM64

Label symbols are only useful for relocations from text. No need
to do it for DWARF. And the PE symbol table doesn't like them.

May fix #51903.

Change-Id: Ibe6ea880d8533ba1dcc017030072c7dffee0e9e5
Reviewed-on: https://go-review.googlesource.com/c/go/+/395215
Trust: Cherry Mui <cherryyz@google.com>
Run-TryBot: Cherry Mui <cherryyz@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>