Fix the wrong number of icons in shelf for RTL

In NotificationShelf, mShelfIcons.setActualLayoutWidth's parameter
comes from the return value of mCollapsedIcons.getFinalTranslationX.
both of mCollapsedIcons.getFinalTranslationX and 'start' has the
operator '+' and mCollapsedIcons.getFinalTranslationX should return
the value that doesn't translate to the xTranslation. The root cause
is that mCollapsedIcons.getFinalTranslationX should return the
'start tranlation' rather xTranslation.

The solution is to make the mixing usage between 'start tranlation'
and xTranslation to be seperated. And, 'start translation' is called
xAnchorStart. To get the 'start translation' by counting
(getWidth() - mLastVisibleIconState.xTranslation - iconWidth) to get
xAnchorStart.

Change-Id: Iec6893446ba161cce50e9b018e43f94782b91f11
Merged-In: Iec6893446ba161cce50e9b018e43f94782b91f11
Fixes: 111861498
Test: manual test
(cherry picked from commit b623343f)