Add allowRedundantMoreKeys attribute

This CL also adds a couple of custom layout tests of Nordic languages.

Bug: 10787354
Change-Id: I5e875d3f30863395511afa82f0a02deb093d3a6f
diff --git a/java/res/values/attrs.xml b/java/res/values/attrs.xml
index 8ee859b..f2072fd 100644
--- a/java/res/values/attrs.xml
+++ b/java/res/values/attrs.xml
@@ -518,6 +518,8 @@
         <attr name="enableProximityCharsCorrection" format="boolean" />
         <!-- Indicates if the keyboard layout supports being split or not. false by default -->
         <attr name="supportsSplitLayout" format="boolean" />
+        <!-- Allow redundant more keys when they are in the base layout. true by default. -->
+        <attr name="allowRedundantMoreKeys" format="boolean" />
     </declare-styleable>
 
     <declare-styleable name="KeyboardLayoutSet_Feature">