Tests: Make the imports of assert*() consistent.

Tests: Make the imports of assert*() consistent.

        * src/test/java/org/glom/web/client/GwtTestOnlineGlom.java:
        * src/test/java/org/glom/web/client/place/DetailsPlaceTest.java:
        * src/test/java/org/glom/web/client/place/ListPlaceTest.java:
        * src/test/java/org/glom/web/server/ConfiguredDocumentTest.java:
        * src/test/java/org/glom/web/server/SelfHostConfiguredDocumentTest.java:
        * src/test/java/org/glom/web/server/SelfHostExampleTest.java:
        * src/test/java/org/glom/web/server/libglom/DocumentTest.java:
        * src/test/java/org/glom/web/server/libglom/LayoutItemFieldTest.java:
        * src/test/java/org/glom/web/server/libglom/LayoutItemPortalDeepCloneTest.java:
        * src/test/java/org/glom/web/shared/DataItemTest.java:
	Just do
	import static org.junit.Assert.*;
	which seems fairly common.