Make Font class being able to create from native instance

This CL refactors followings:
- Use infomation stored in native instance as the source-of-truth.
- Being able to create Font instance from native instance.
- Use ByteBuffer as a wrapper of the native byte buffer.

Bug: 179113771
Test: atest CtsTextTestCases CtsGraphicsTestCases
Test: atest android.graphics.fonts.NativeSystemFontTest
Test: atest android.graphics.fonts.SystemFontsTest
Test: atest FrameworksCoreTests:android.text
Test: atest FrameworksCoreTests:android.graphics
Change-Id: Icc1df1c76ba78d4f8800984444439fd03970e179