Add icudtl.dat to the list of files to copy for WebKitUnitTests

icudtl.dat is not copied to an Android device for webkit_unit_tests
leading to the failure of tests depending on ICU.

Add icu.isolate explicitly to get icudtl.dat copied.

TBR=jamesr@chromium.org
BUG=72633
TEST=build/android/test_runner.py gtest -s webkit_unit_tests --verbose
--gtest_filter=WebFrameTest.SelectRange*

Review URL: https://codereview.chromium.org/183013006

git-svn-id: svn://svn.chromium.org/blink/trunk@168506 bbb929c8-8fbe-4397-9dbb-9b2b20218538