The default alignment of the text in wxSpinCtrl was changed to "right"
in 7e4952db83
, which added alignment
support (see #10621), but this made it inconsistent with the native
up-down control under MSW and, perhaps more importantly, with spin
controls created from XRC as the default style was never modified there
and did not include wxALIGN_RIGHT.
Resolve this inconsistency by reverting to left-aligning the text by
default.