suggest collection utility methods in basic completion on non-empty prefix

java/java-tests/testData/codeInsight/completion/normal/SuggestEmptySet_after.java

@@ -0,0 +1,8 @@
+import java.util.Collections;
+import java.util.Set;
+
+class Foo {
+  {
+    Set<String> s = Collections.emptySet()<caret>
+  }
+}