blacklist svMatrix for calc threaded calculation

If a formula contains a matrix, interpreting it will actually result
in modifying it in some ways (e.g. ScInterpreter::PopRangeMatrix() calls
SetErrorInterpreter() on the matrix).
Testcase: rhbz#1645905

Change-Id: I63742449ba0e4e375d6e459dc7bccd7e6b62920e
Reviewed-on: https://gerrit.libreoffice.org/63187Reviewed-by: Michael Meeks <michael.meeks@collabora.com>
Tested-by: Jenkins

sc/source/core/tool/token.cxx

@@ -1334,6 +1334,7 @@ void ScTokenArray::CheckForThreading( const FormulaToken& r )
             case svExternalDoubleRef:
             case svExternalSingleRef:
             case svExternalName:
+            case svMatrix:
                 SAL_INFO("sc.core.formulagroup", "opcode ocPush: variable type " << StackVarEnumToString(r.GetType())
                     << " disables threaded calculation of formula group");
                 mbThreadingEnabled = false;