java completion: use context substitutor even for methods whose type parameters can be inferred from parameter types (IDEA-148623)

java/java-tests/testData/codeInsight/completion/normalSorting/PreferCollectionsStaticOfExpectedType.java

@@ -0,0 +1,9 @@
+import java.util.*;
+
+public class MainClass1 {
+
+  List<String> foo(){
+    return Collections.un<caret>
+  }
+}
+