[gui-test] add doubleClickItem(item) extension function for JListFixture to GuiTestCase and Generators

platform/testGuiFramework/src/com/intellij/testGuiFramework/generators/Generators.kt

@@ -126,6 +126,7 @@ class JBListGenerator : ComponentCodeGenerator<JBList<*>> {
     val cellText = getCellText(cmp, cp).orEmpty()
     if (cmp.isPopupList()) return "popupClick(\"$cellText\")"
     if (me.button == MouseEvent.BUTTON2) return "jList(\"$cellText\").item(\"$cellText\").rightClick()"
+    if (me.clickCount == 2) return "jList(\"$cellText\").doubleClickItem(\"$cellText\")"
     return "jList(\"$cellText\").clickItem(\"$cellText\")"
   }
 }

platform/testGuiFramework/src/com/intellij/testGuiFramework/impl/GuiTestCase.kt

@@ -378,6 +378,10 @@ open class GuiTestCase : GuiTestBase() {
 
   //*********SOME EXTENSION FUNCTIONS FOR FIXTURES
 
+  fun JListFixture.doubleClickItem(itemName: String) {
+    this.item(itemName).doubleClick()
+  }
+
   //necessary only for Windows
   fun getScaleSuffix(): String? {
     val scaleEnabled: Boolean = (GuiTestUtil.getSystemPropertyOrEnvironmentVariable("sun.java2d.uiScale.enabled")?.toLowerCase().equals(