Revert of Enable icu_use_data_file on Windows (https://codereview.chromium.org/99473012/)

Reason for revert:
mini_installer somehow does not install icudtl.dat in the top product directory (alongside chrome.exe) leading to a failure in InitializeICU(). 

icudtl.dat is listed in both mini_installer.gypi and FILES.cfg for windows.


Original issue's description:
> Enable icu_use_data_file on Windows
> 
> 
> Set icu_use_data_file_flag to 1 on Windows in common.gypi and make the dependency on icudata conditional on 'icu_use_data_file_flag != 0' in common.gypi, base.gyp and net.gyp
> 
> This also requires a change in third_party/icu/icu.gyp
> ( https://codereview.chromium.org/111723007/ ), which was rolled in by https://codereview.chromium.org/118313004/
> 
> BUG=72633
> TEST=All windows builds work fine and there's no perf regression (start-up etc).
> 
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=246387

TBR=mark@chromium.org,scottmg@chromium.org,laforge@chromium.org,maruel@chromium.org,grt@chromium.org,wtc@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=72633

Review URL: https://codereview.chromium.org/139403006

git-svn-id: http://src.chromium.org/svn/trunk/src/build@246632 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

common.gypi

@@ -1287,7 +1287,6 @@
       }],
       ['OS=="win"', {
         'windows_driver_kit_path%': '$(WDK_DIR)',
-        'icu_use_data_file_flag%': 1,
       }],
       ['os_posix==1 and OS!="mac" and OS!="ios"', {
         'conditions': [