sc: Drop ineffective SetError()

as GetNewMat() already sets error FormulaError::MatrixSize
when returning null.  In fact IllegalArgument is irrelevant
here.

Change-Id: Ib7354c2e861b666deef1353b2c26d876668d77e3
Reviewed-on: https://gerrit.libreoffice.org/64420
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>

sc/source/core/tool/interpr5.cxx

@@ -438,10 +438,7 @@ ScMatrixRef ScInterpreter::GetMatrix()
             PopExternalSingleRef(pToken);
             pMat = GetNewMat( 1, 1, true);
             if (!pMat)
-            {
-                SetError( FormulaError::IllegalArgument);
                 break;
-            }
             if (nGlobalError != FormulaError::NONE)
             {
                 pMat->PutError( nGlobalError, 0, 0);