Allow building the dump_syms tool on Windows

The Windows target was not ported from gyp, until now.
We're building dump_syms on Windows in Opera so I though I'd share the patch.

BUG=245456

Review-Url: https://codereview.chromium.org/2712423002
Cr-Original-Commit-Position: refs/heads/master@{#458759}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 143d45a4d37530b757f17f9c308412064c7d053e