bug: LIKE with custom escape char produces incorrect results

[andygrove]

Describe the bug

Repro test case for CometExpressionSuite:

  test("like with custom escape") {
    val names = Seq("", "a_b", "d_e_f")
    withTempDir { dir =>
      val filename = "/tmp/percent.parquet"
      names.toDF("a").write.mode(SaveMode.Overwrite).parquet(filename)
      spark.read.parquet(filename).coalesce(1).createOrReplaceTempView("t")
      val query = sql("select a from t where a like '%$_%' escape '$'")
      checkSparkAnswerAndOperator(query)
    }
  }

Output:

== Results ==
!== Correct Answer - 2 ==   == Spark Answer - 0 ==
!struct<a:string>           struct<>
![a_b]                      
![d_e_f]   

Steps to reproduce

No response

Expected behavior

No response

Additional context

No response

[andygrove]

note that we could choose to fallback to spark if there is a custom escape character