coverity#1439335 silence Explicit null dereferenced

and

coverity#1439331 Explicit null dereferenced

Change-Id: Ic9de4d4975cc1721fe5064b2cb8f41b819cf1f98
Reviewed-on: https://gerrit.libreoffice.org/60521Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>

sw/source/core/crsr/findattr.cxx

@@ -476,6 +476,7 @@ bool SwAttrCheckArr::SetAttrFwd( const SwTextAttr& rAttr )
         }
         if( pIter )
         {
+            assert(pSet && "otherwise no pIter");
             nWhch = pIter->NextWhich();
             while( nWhch &&
                 SfxItemState::SET != pSet->GetItemState( nWhch, true, &pTmpItem ) )
@@ -627,6 +628,7 @@ bool SwAttrCheckArr::SetAttrBwd( const SwTextAttr& rAttr )
         }
         if( pIter )
         {
+            assert(pSet && "otherwise no pIter");
             nWhch = pIter->NextWhich();
             while( nWhch &&
                 SfxItemState::SET != pSet->GetItemState( nWhch, true, &pTmpItem ) )