reftests: Use longer words when testing wrapping

"Hello" might be shorter than "Hi Ho" in some fonts and then that one
gets wrapped, too.

So choose perfectly cromulent words for this purpose instead.

testsuite/reftests/vbox-with-2-wrapping-labels-where-one-should-wrap.ref.ui

@@ -9,8 +9,8 @@
             <property name="orientation">1</property>
             <child>
               <object class="GtkLabel">
-                <property name="label">Hello
-World</property>
+                <property name="label">perfectly
+cromulent</property>
               </object>
             </child>
             <child>

testsuite/reftests/vbox-with-2-wrapping-labels-where-one-should-wrap.ui

@@ -9,7 +9,7 @@
             <property name="orientation">1</property>
             <child>
               <object class="GtkLabel">
-                <property name="label">Hello World</property>
+                <property name="label">perfectly cromulent</property>
                 <property name="wrap">1</property>
                 <property name="max-width-chars">1</property>
               </object>