Calculate set of available fonts in native

The previous attempt[1] of improving SystemFonts API is not good enough
for users. To further improve the performance, calculate font uniqueness
in native code. From Android S, the system font information is stored
in native code and has more information for skipping duplication check.

Bug: 188201287
Test: atest FontFamilyUpdateRequestTest
Test: atest FontListParserTest
Test: atest FontManagerTest
Test: atest NativeSystemFontTest
Test: atest PersistentSystemFontConfigTest
Test: atest SystemFontsTest
Test: atest SystemFontsUniqueNameTest
Test: atest UpdatableFontDirTest
Test: atest UpdatableSystemFontTest
Test: minikin_tests
Change-Id: Ib375dcda0f278c93ec8dd21636d7a22b4174f214