Stop Scintilla timer when the control doesn't have focus.

This avoids excessive CPU load due to generating completely unnecessary timer
notifications for every wxSTC control in a program.

Closes #14938.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@76665 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/stc/ScintillaWX.cpp

@@ -941,6 +941,7 @@ void ScintillaWX::DoLoseFocus(){
     SetFocusState(false);
     focusEvent = false;
     DestroySystemCaret();
+    SetTicking(false);
 }
 
 void ScintillaWX::DoGainFocus(){
@@ -949,6 +950,7 @@ void ScintillaWX::DoGainFocus(){
     focusEvent = false;
     DestroySystemCaret();
     CreateSystemCaret();
+    SetTicking(true);
 }
 
 void ScintillaWX::DoSysColourChange() {