Infinite loop in ooo32227-1.rtf with calc rtf filter

Change-Id: I068b205c844296379b5641356e4087b17f0a3535
Reviewed-on: https://gerrit.libreoffice.org/44218Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>

svtools/source/svrtf/parrtf.cxx

@@ -336,7 +336,9 @@ void SvRTFParser::ScanText()
                             sal_Char nSlash = '\\';
                             while (!bBreak)
                             {
-                                wchar_t next=GetNextChar();
+                                auto next = GetNextChar();
+                                if (sal_Unicode(EOF) == next)
+                                    break;
                                 if (next>0xFF) // fix for #i43933# and #i35653#
                                 {
                                     if (!aByteString.isEmpty())