Fix RTL appearance of new ToC icons

We had initially resolved the arrow-direction issue on RTL here by
swapping the two glyphs, but this put the arrow on the wrong side
of the greeked text representation in the icon.

Flipping it with a transform *seems* to work fine.
Tested in 6.1, 7.1, and 8.0.

Bug: 70491
Change-Id: Id63bf72ee5a09704f994102b19ea265dd89718a1