Don't run win_helper.py get-visual-studio-data on non-Windows
Don't run win_helper.py get-visual-studio-data on non-Windows

Apart from being pointless, the script errors out on e.g. Fuchsia
because python doesn't have a _winreg module.

Bug: crashpad:79
Change-Id: Ia506613220f0dc818ff959c8e1d86d852cd9ae88
Reviewed-on: https://chromium-review.googlesource.com/907414
Reviewed-by: Mark Mentovai <f1b5a91d4d6ad523f2610114591c007e75d15084@chromium.org>

chromium/mini_chromium,chromium/mini_chromium,chromium/mini_chromium