All system font files are file backed and stored in the unique place,
so no need to compare the buffers during creating sets of system fonts.
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
Change-Id: I4a4680937988c013aaa4e4fa729e61ac8514c513