[gtksourceview] testwidget: remove unnecessary code

[Christian Hergert <chergert src gnome org>]

commit 5dc3f96ccf74d7719887e3a217fef2bdbd1159d3
Author: Christian Hergert <chergert redhat com>
Date:   Thu Oct 14 17:48:01 2021 -0700

    testwidget: remove unnecessary code
    
    We have .GtkSourceMap now

 tests/test-widget.ui | 3 ---
 1 file changed, 3 deletions(-)
---
diff --git a/tests/test-widget.ui b/tests/test-widget.ui
index 4843e036..d6c28888 100644
--- a/tests/test-widget.ui
+++ b/tests/test-widget.ui
@@ -472,9 +472,6 @@
             <property name="visible">True</property>
             <property name="can_focus">False</property>
             <property name="view">view</property>
-            <style>
-              <class name="map"/>
-            </style>
             <layout>
               <property name="column">2</property>
               <property name="row">0</property>