Remove SystemFonts#getSystemFallback and use Typeface instead for fallback

Bug: 173752727
Test: atest CtsTextTestCases
Test: atest CtsGraphicsTestCases
Test: atest TextViewTests
Test: atest TypefaceSystemFallbackTest
Test: atest TypefaceTest
Change-Id: I1c242ef6f651876e83d72fc5620035805fed2475
3 files changed