Don't unnecessarily NUL-terminate wxCharBuffer contents.

wxCharBuffer already initializes the last byte of the buffer it allocates to 0
so there is no need to do it explicitly.

Also don't allocate an extra byte, wxCharBuffer already adds one to the length
passed to it for the trailing NUL.

See #13885.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@73141 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/common/strconv.cpp

@@ -460,7 +460,6 @@ wxMBConv::cMB2WC(const char *inBuff, size_t inLen, size_t *outLen) const
         // because we want the buffer to always be NUL-terminated, even if the
         // input isn't (as otherwise the caller has no way to know its length)
         wxWCharBuffer wbuf(dstLen);
-        wbuf.data()[dstLen] = L'\0';
         if ( ToWChar(wbuf.data(), dstLen, inBuff, inLen) != wxCONV_FAILED )
         {
             if ( outLen )