Add android_small/icudatl_extra.dat

This newly built DAT file contains new locales for Android:
      "bn", "et", "gu", "kn", "ml", "mr", "ms", "ta", "te", "af",
      "az", "eu", "gl", "hy", "is", "ka", "kk", "km", "ky", "lo",
      "mk", "mn", "my", "ne", "pa", "si", "sq", "ur", "uz", "zu"

It can be used in conjunction with android_small/icudtl.dat
The application (chrome on android) should load the icudtl_extra.dat
FIRST before loading android_small/icudtl.dat

To work around the limitation of ICU's handling of multiple data packages, the following is done for android_small/icudatl_extra.dat.

a. Do not use pool bundles. usePoolBundle is set to false in android_extra.json.
b. Filter out res_index.res files with "icupkg -r"

Bug: chromium:969181
Change-Id: I9a3407bfcbe4a55e1f9bda1daa713e4487fbfbba
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/deps/icu/+/1648623
Reviewed-by: Jungshik Shin <jshin@chromium.org>
7 files changed