Followon fix for 14276128 Clipping at bottom of TextView

The previous fix did not work when the text was ellipsized, because the
test for whether the line was the last line was incorrect. The new test
handles both the end of the buffer and the case where it is the last
line because of ellipsizing.

So this should be the proper fix for bug 14276128 Clipping at bottom of
TextView when lineSpacingMultiplier < 1

This version of the patch also handles the single-line case (which is
computed in BoringLayout rather than StaticLayout).

Change-Id: I88791acc2aa493cc8c599b374f4d213571260b4b