Improve the DruidRexExecutor w.r.t handling of numeric arrays

[LakshSingla]

Description

Issue:
DruidRexExecutor while reducing Arrays, specially numeric arrays, doesn't convert the value from ExprResult's type to BigDecimal, which causes makeLiteral to cast the values. Also, if NaN or Infinite values are present in the array, the error is a generic NumberFormatException. For example:

SELECT ARRAY[1.11, 2.22] returns [1, 2]
SELECT SQRT(-1) throws a generic NumberFormatException instead of IAE

This PR introduces change to cast the numeric values to BigDecimal since Calcite's library understands that easily, and doesn't perform casts.

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Key changed/added classes in this PR

• DruidRexExecutor#reduce()

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This PR has:

• been self-reviewed.
  • using the concurrency checklist (Remove this item if the PR doesn't have any relation to concurrency.)
• added documentation for new or modified features or behaviors.
• added Javadocs for most classes and all non-trivial methods. Linked related entities via Javadoc links.
• added or updated version, license, or notice information in licenses.yaml
• added comments explaining the "why" and the intent of the code wherever would not be obvious for an unfamiliar reader.
• added unit tests or modified existing tests to cover new code paths, ensuring the threshold for code coverage is met.
• added integration tests.
• been tested in a test Druid cluster.

[clintropolis]

👍 could you add a test for this in https://github.com/apache/druid/blob/master/sql/src/test/java/org/apache/druid/sql/calcite/planner/DruidRexExecutorTest.java

[LakshSingla]

Added the testcases, and fixed the older incorrect ones which were known.

[abhishekagarwal87]

LGTM

[rohangarg]

would be better if you can add a check for double type here

[LakshSingla]

An else case is required to stop the "Variable might not have been initialized" exception from cropping up, and I didn't want to provide a failsafe else block. In case when it's not an array (https://github.com/LakshSingla/druid/blob/4dcdb2d68563302a9b4d387cdbb220ec4f3a59b3/sql/src/main/java/org/apache/druid/sql/calcite/planner/DruidRexExecutor.java#L130), it was using the else case as well, that's why I omitted the else if.
One approach can be to initialize the literal to null and then including your suggestion. Let me know if that seems better, and I can add that in a separate commit.