don't erase generics when choosing a new class name with tab (IDEA-50622)

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

@@ -0,0 +1,9 @@
+public class TestClass {
+
+    public TestClass create() {
+        final int value = 1;
+        return new Xxx<caret><String>(value);
+    }
+}
+
+class Xxx { }