Include java.lang.Lang from java.util.Util.

This is necessary now that our java.util contains classes that use java.lang.InterruptedException.

In short:

Before:
<module>
 <super-source path="super"/>
</module>

After:
<module>
 <super-source path="super"/>
 <inherits name="java.lang.Lang"/>
</module>

Fixes #2638

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=138904012

guava-gwt/src-super/java/util/Util.gwt.xml

@@ -1 +1,6 @@
-<module><super-source path="super"/></module>
+
+<module>
+ <super-source path="super"/>
+ <inherits name="java.lang.Lang"/>
+</module>
+