Revert "Add font extent calculation"
Revert "Add test case for fallback line spacing"
Revert submission 16486662-fallback_line_spacing
Reason for revert: Investigate test failures on master
BUGID: b/213826416
BUGID: b/213829920
Reverted Changes:
I06cd7ab71:Add font extent calculation
I6214d52cd:Implement fallback line spacing for BoringLayout
Ia5825c474:Add test case for fallback line spacing
Change-Id: Ia6d6f9f44e73ddaf5e8fe9a8aead7a53efbddd44