Fix StaticLayout.mDirections array size

mLineDirections variable needs to keep a Directions object for each line
of text. Therefore at any time array of line count is required. However
currently mLineDirections is initialized and grown in the size of mLines
array, which makes the size around mColumns*line count.

This CL removes that extra allocation.

Test: Manual test to check if device boots and displays
Test: bit -t CtsTextTestCases:*
Test: bit -t FrameworksCoreTests:android.text.
Test: bit -t FrameworksCoreTests:android.widget.TextViewTest
Test: bit -t FrameworksCoreTests:android.widget.EditorCursorTest
Test: bit -t CtsWidgetTestCases:android.widget.cts.TextViewTest
Test: bit -t CtsWidgetTestCases:android.widget.cts.EditTextTest

Bug: 64038460
Bug: 62889232
Change-Id: If9bda040b98efcf16c3cdcba5bc27667775ce1fc