This is necessary to make ninjalog_uploader_wrapper.py exit without
waitinng finish of ninjalog_uploader.py in windows.

Bug: 992282
Change-Id: I69d11074bcbe5d0958468a9c8ec8391b0741a839
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/2237269
Auto-Submit: Takuto Ikuta <tikuta@chromium.org>
Reviewed-by: Yoshisato Yanagisawa <yyanagisawa@chromium.org>
Commit-Queue: Takuto Ikuta <tikuta@chromium.org>