tests: add an isolated test case for long struct names with capitalization

vlib/v/tests/differently_named_structs_test.v

@@ -0,0 +1,16 @@
+
+struct DB { name string }
+struct DxB { name string }
+struct DeclExprA { name string }
+struct AStructWithAVeryLongName { name string }
+
+fn test_struct_names_can_be_used_for_creating_them() {
+   a := DB{}
+   assert true
+   b := DxB{}
+   assert true
+   c := DeclExprA{}
+   assert true
+   d := AStructWithAVeryLongName{}
+   assert true
+}