Merge "Move icu related hidden API flag file contents to icu" am: 653935b511 am: e8cf665edd am: f27b828bf9

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/1675890

Change-Id: Id534f0ec692848bbb6c99074bcd4a7e92c0df9ce