eeschema: Limit normalization on load

When loading a new file, we do not want to add junctions where they did
not exist before.  This could generate invalid netlists by breaking a
wire at a pin connection point.

We do break/add connections when the user modifies the schematic but
this happens while the user is actively working with the component and
sees the action.

Fixes: lp:1830411
* https://bugs.launchpad.net/kicad/+bug/1830411

eeschema/bus-wire-junction.cpp

@@ -272,15 +272,13 @@ bool SCH_EDIT_FRAME::AddMissingJunctions( SCH_SCREEN* aScreen )
 
 void SCH_EDIT_FRAME::NormalizeSchematicOnFirstLoad( bool recalculateConnections )
 {
-    if( recalculateConnections )
-        RecalculateConnections();
-    else
-        SchematicCleanUp();
-
     SCH_SHEET_LIST list( g_RootSheet );
 
     for( const auto& sheet : list )
-        AddMissingJunctions( sheet.LastScreen() );
+        SchematicCleanUp( sheet.LastScreen() );
+
+    if( recalculateConnections )
+        RecalculateConnections( false );
 }