Revert "Implement fallback line spacing for BoringLayout"

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