Fix a search pane crash when a row isn't in the hit list.

Fixes KICAD-Q7
Fixes KICAD-1A6

eeschema/widgets/search_handlers.h

@@ -48,7 +48,15 @@ public:
 
     wxString GetResultCell( int aRow, int aCol ) override
     {
-        return getResultCell( m_hitlist[aRow], aCol );
+        if( aRow >= m_hitlist.size() )
+            return wxEmptyString;
+
+        const SCH_SEARCH_HIT& hit = m_hitlist[aRow];
+
+        if( !hit.item )
+            return wxEmptyString;
+
+        return getResultCell( hit, aCol );
     }
 
     void FindAll( const std::function<bool( SCH_ITEM*, SCH_SHEET_PATH* )>& aCollector );

pcbnew/widgets/search_handlers.h

@@ -39,7 +39,15 @@ public:
 
     wxString GetResultCell( int aRow, int aCol ) override
     {
-        return getResultCell( m_hitlist[aRow], aCol );
+        if( aRow >= m_hitlist.size() )
+            return wxEmptyString;
+
+        BOARD_ITEM* item = m_hitlist[aRow];
+
+        if( !item )
+            return wxEmptyString;
+
+        return getResultCell( item, aCol );
     }
 
     void Sort( int aCol, bool aAscending ) override;