[SPARK-34157][BUILD][FOLLOW-UP] Fix Scala 2.13 compilation error via using Array.deep

[HyukjinKwon]

What changes were proposed in this pull request?

This PR is a followup of #31245:

[error] /home/runner/work/spark/spark/sql/core/src/test/scala/org/apache/spark/sql/execution/command/v1/ShowTablesSuite.scala:112:53: value deep is not a member of Array[String]
[error]         assert(sql("show tables").schema.fieldNames.deep ==
[error]                                                     ^
[error] /home/runner/work/spark/spark/sql/core/src/test/scala/org/apache/spark/sql/execution/command/v1/ShowTablesSuite.scala:115:72: value deep is not a member of Array[String]
[error]         assert(sql("show table extended like 'tbl'").schema.fieldNames.deep ==
[error]                                                                        ^
[error] /home/runner/work/spark/spark/sql/core/src/test/scala/org/apache/spark/sql/execution/command/v1/ShowTablesSuite.scala:121:55: value deep is not a member of Array[String]
[error]           assert(sql("show tables").schema.fieldNames.deep ==
[error]                                                       ^
[error] /home/runner/work/spark/spark/sql/core/src/test/scala/org/apache/spark/sql/execution/command/v1/ShowTablesSuite.scala:124:74: value deep is not a member of Array[String]
[error]           assert(sql("show table extended like 'tbl'").schema.fieldNames.deep ==
[error]                                                                          ^

It broke Scala 2.13 build. This PR works around by using ScalaTests' === that can compare Arrays safely.

Why are the changes needed?

To fix the build.

Does this PR introduce any user-facing change?

No, dev-only.

How was this patch tested?

CI in this PR should test it out.

[cloud-fan]

thanks for fixing!

[HyukjinKwon]

Okay, Scala 2.13 build passes. I manually tested that it fixes the tests too locally. Let me merge this in to unblock other PRs.

[SparkQA]

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[SparkQA]

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[beliefer]

@HyukjinKwon Thanks for your fix!