Non-RexInputRef may fails the matching of FilterToProjectUnifyRule during 'invert' by mistake.

  @Test public void testFilterToProject0() {
    String union =
        "select * from \"emps\" where \"empid\" > 300\n"
            + "union all select * from \"emps\" where \"empid\" < 200";
    String mv = "select *, \"empid\" * 2 from (" + union + ")";
    String query = "select * from (" + union + ") where (\"empid\" * 2) > 3";
    checkMaterialize(mv, query);
  }

  @Test public void testFilterToProject1() {
    String agg =
        "select \"deptno\", count(*) as \"c\", sum(\"salary\") as \"s\"\n"
            + "from \"emps\" group by \"deptno\"";
    String mv = "select \"c\", \"s\", \"s\" from (" + agg + ")";
    String query = "select * from (" + agg + ") where (\"s\" * 0.8) > 10000";
    checkNoMaterialize(mv, query, HR_FKUK_MODEL);
  }