Don't create labels with wxST_NO_AUTORESIZE flag with empty size by default.

Don't create labels with wxST_NO_AUTORESIZE flag with empty size by default.

Since r57627 wxStaticText objects with wxST_NO_AUTORESIZE flag created with
wxDefaultSize were created with zero width. This accounted for the
disappearance of the labels for the toolbar controls (as could be seen in the
toolbar sample where the combobox label was not shown any more).

Fix this by explicitly setting the correct initial size after the correct
label is set.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@62935 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775