Toolchain crashes on build machines are an ongoing problem, particularly
with the VC++ 2015 migration. Setting this registry key tells Windows
Error Reporting to record minidumps (a few MB typically) to a local
directory, up to a maximum of ten. This should help with investigations.

This change also suppresses Windows Error Reporting dialogs with the
DontShowUI registry value, to avoid builder hangs on crashes.

See also crrev.com/1816333002

BUG=440500

Review URL: https://codereview.chromium.org/1825163003

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@299426 0039d316-1c4b-4281-b951-d872f2087c98