Set correct toolbar width in wxMSW wxFrame.

Set correct toolbar width in wxMSW wxFrame.

The hack introduced in r22410 artificially set wrong size for toolbar under
MSW. This completely breaks any calculations that can be done using it (e.g.
to find the space available for the stretchable part of the toolbar) and is
completely and utterly unexpected.

Revert it, toolbar flicker must be dealt in another way if it is still a
problem.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@62848 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775