[INTERNAL][FIX]sap.m List: Header Toolbar has wrong font size.

- The label font size  used as Toolbar Header should be
@sapMFontHeader4Size
- ToolbarSpacer should respect shrinking for IE10.

Change-Id: I3188155b8ad4dd1f7e52c78f3c2d93742698610a
Merge "[INTERNAL][FIX]sap.m List: Header Toolbar has wrong font size."