Keep source ID into native object

To avoid static field and synchronization for the mapping, keep source
identifier into native font instance.

Bug: 179113771
Test: minikin_tests
Test: hwui_unit_tests
Test: atest CtsTextTestCases CtsGraphicsTestCases
Change-Id: I238e7b8090ee89101937ec22cbe7c68aea97bcfd
8 files changed