Revert "win: Make chrome.7z generation more deterministic."

This reverts commit e2a95639125afd08739a36d0e7f367f7b8abb952.

Reason for revert: This breaks tests on account of fooling the Windows loader. See https://bugs.chromium.org/p/chromium/issues/detail?id=900121#c6 for details.

Original change's description:
> win: Make chrome.7z generation more deterministic.
> 
> mini_installer.exe embeds chrome.7z, and chrome.7z contains timestamps
> of all files in the archive. To make chrome.7z more deterministic, give
> all files in it deterministic timestamps.
> 
> Bug: 330260
> Change-Id: Ia251dd38177acbebdde288b86826986f441b2d4d
> Reviewed-on: https://chromium-review.googlesource.com/c/1302393
> Reviewed-by: Gabriel Charette <gab@chromium.org>
> Commit-Queue: Nico Weber <thakis@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#603171}

TBR=gab@chromium.org,thakis@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: 330260
Change-Id: I261401c27226ab9e0cf30bc07a47ecf8399f491b
Reviewed-on: https://chromium-review.googlesource.com/c/1317569
Reviewed-by: Greg Thompson <grt@chromium.org>
Commit-Queue: Greg Thompson <grt@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#605299}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 05eb6e237704dc0e3fcdaac39ac35edb71c0cb58

write_build_date_header.py

@@ -13,10 +13,10 @@ import sys
 def main():
   argument_parser = argparse.ArgumentParser()
   argument_parser.add_argument('output_file', help='The file to write to')
-  argument_parser.add_argument('timestamp', type=int)
+  argument_parser.add_argument('timestamp')
   args = argument_parser.parse_args()
 
-  date = datetime.datetime.utcfromtimestamp(args.timestamp)
+  date = datetime.datetime.utcfromtimestamp(int(args.timestamp))
   output = ('// Generated by //build/write_build_date_header.py\n'
            '#ifndef BUILD_DATE\n'
            '#define BUILD_DATE "{:%b %d %Y %H:%M:%S}"\n'