cmd/link/internal/wasm: do not generate more than 100000 data segments

Some WebAssembly runtimes (e.g. Node.js) fail to load a wasm binary if
it has more than 100000 data segments. Do not skip zero regions any more
if the limit was reached.

Change-Id: I14c4c2aba142d1d2b887bce6d03b8c1c1746c5ec
Reviewed-on: https://go-review.googlesource.com/c/go/+/168884


Run-TryBot: Richard Musiol <neelance@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>