We shouldn't add thousands separators nor remove trailing zeros for the numbers in scientific format. Also avoid "-0" as output. See #15625. [This is the backport of r75560 from trunk.] git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/WX_3_0_BRANCH@77959 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775