Remove font file name dependency

The font file name is no longer used for creating mapping.

Bug: 184003133
Test: atest UpdatableFontDirTest
Test: atest FontManagerTest
Test: atest UpdatableSystemFontTest
Test: atest FontFamilyUpdateRequestTest
Test: atest PersistentSystemFontConfigTest
Test: atest android.graphics.fonts.SystemFontsUniqueNameTest
Change-Id: I83520b14926c8afa3cae988ef59c53d96fb0b8fd