Return Windows error code when create-process fails.

COULD_NOT_CREATE_PROCESS makes up about 10% of the setup errors; include the actual DWORD result code returned by ::CreateProcess by placing all result information into the proper location of the Registry for reading by Omaha.

BUG=

Committed: https://crrev.com/135f5f669574bd07eaedaf6b57503984aeb13be8
Cr-Commit-Position: refs/heads/master@{#341938}

Review URL: https://codereview.chromium.org/1247993002

Cr-Commit-Position: refs/heads/master@{#342528}
12 files changed