Work around a breakpad bug on Windows

[RichardTea]

Breakpad updated to Python3 and this appears to have broken Google depot_tools fetch.bat and gclient.bat on Windows. Sadly, updating depot_tools alone was not enough!

Work around the issue by:

• Move the Windows breakpad setup into a batch file to catch the return code.
• Manually call the Python script named in the DEPS hook if it fails.
• Allow the gclient.bat sync call to fail without aborting the build

This workaround can be removed once upstream fixes the issue.