[dev.link] cmd/link: remove -newdw flag for phase 1 DWARF gen
Remove the "-newdw" command line option, a temporary placeholder/gate
for the first phase of new DWARF gen, along with some portions of the
sym.Symbol based DWARF type gen code. The remainder of the old code
will be removed in a subsequent patch.
Change-Id: I7870539f020fbf05d0345d3af2acf383fae94892
Reviewed-on: https://go-review.googlesource.com/c/go/+/220984
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Cherry Zhang <cherryyz@google.com> Reviewed-by: Jeremy Faller <jeremy@golang.org>