Remove obsolete interface GetTable.

GetTable is only used in test.
To use production interface, need to pass the raw buffer and size to the
MinikinSkia.  This CL does not change any production behaviors.

Test: ran hwui microbench, macrobench, hwui_unit_tests
Change-Id: Ia657a0d061984d705f333ed3944effb1eba8ca4d