Improve ellipsize performance

Instead of iterate all ellipsized characters, only iterate the necessary
ranges for copying.

Bug: 188913943
Test: atest CtsTextTestCases CtsGraphicsTestCases CtsWidgetTestCases
Change-Id: I3d03b1e3897e427c23fbe51315f412c57a4ce9e9
(cherry picked from commit 2c6121f3e3c52965ae33317e4fe7a273fd1742c6)
(cherry picked from commit 40d7a4535aba93073264bf8998daf588f0923986)
1 file changed