Add support for icu_use_data_file=1 to icu.gyp on Windows/Linux

1. When icu_use_data_file_flag is set to 1 on Windows, we don't need
to copy icudt.dll. Instead, we have to copy icudt*.dat.

2. Put copies statement for icudt*.dat outside link_settings on all platforms.

For static builds on Linux, Windows and Mac,
'copies' should be pulled out of 'link_settings'. Putting it outside
'link_settings' does not hurt shared builds, either.


iOS is the only platform with icu_use_data_file=1 at the moment and
is affected directly by this CL (dropping link_settings).

3. Simplify the condition for mac_bundle_resource by dropping
'OS=="mac" and _mac_bundle' because it's never satisfied here.

4. Rename icudt46l.dat in source/data/in and android to icudtl.dat. This
is to simplify the ICU upgrade process down the road.
With the version number removed, there's no need to change the data filename
in multiple gyp files and windows package configuration files when upgrading
ICU. (the same was done for icudt.dll on Windows a few years ago.)

This CL has to go first before we land the chromium-side changes
to set icu_use_data_file to 1 on
Windows (https://codereview.chromium.org/99473012 ),
Linux ( https://codereview.chromium.org/102413007 ), and
Mac ( https://codereview.chromium.org/109013004 )

The chromium-side change for Mac will follow this, too.

BUG=72633
TEST=None (until this is rolled).
R=mark@chromium.org, scottmg@chromium.org

Review URL: https://codereview.chromium.org/111723007

git-svn-id: https://src.chromium.org/chrome/trunk/deps/third_party/icu46@241597 4ff67af0-8c30-449e-8e8b-ad334ec8d88c