Test for 29475 Element Collection issue

[ajaypaul-ibm]

• I have considered the risk of behavior change or other zero migration impact (https://github.com/OpenLiberty/open-liberty/wiki/Behavior-Changes).
• If this PR fixes an Issue, the description includes "Fixes #FILLMEIN" or "Resolves #FILLMEIN" (verify release bug label if applicable: https://github.com/OpenLiberty/open-liberty/wiki/Open-Liberty-Conventions).
• If this PR resolves an external Known Issue (including APARS), the description includes "Fixes #FILLMEIN" or "Resolves #FILLMEIN".
  for JPQL SELECT NEW not joining nor recogning ElementCollection as a collection type #29475
  This demonstrates that EclipseLink is allowing ElementCollection attributes to be returned by JPQL queries, but with results that are both inconsistent with non-ElementCollection attributes of the same type, and are also incorrect. Especially when returning multiple results which get erroneously combined together into a single collection!

Here is the output of this test. Entity attribute names ending in "EC" use ElementCollection. The others have the same types but don't use ElementCollection:

SELECT intArray FROM ECEntity WHERE id=?1
getResultList returned a java.util.Vector
    elements are of type int[]
            contents are [[14, 12, 1]]

SELECT longList FROM ECEntity WHERE id=?1
getResultList returned a java.util.Vector
    elements are of type java.util.ArrayList
            contents are [[14, 12, 1]]

SELECT stringSet FROM ECEntity WHERE id=?1
getResultList returned a java.util.Vector
    elements are of type java.util.ImmutableCollections$SetN
            contents are [[fourteen, twelve, one]]

SELECT longListEC FROM ECEntity WHERE id=?1
getResultList returned a java.util.Vector
    elements are of type java.lang.Long
            contents are [14, 12, 1]

SELECT longListEC FROM ECEntity WHERE id LIKE ?1
getResultList returned a java.util.Vector
    elements are of type java.lang.Long
            contents are [14, 12, 1, 14, 12, 2]

SELECT longList FROM ECEntity WHERE id LIKE ?1
getResultList returned a java.util.Vector
    elements are of type java.util.ArrayList
            contents are [[14, 12, 1], [14, 12, 2]]

SELECT stringSetEC FROM ECEntity WHERE id LIKE ?1
getResultList returned a java.util.Vector
    elements are of type java.lang.String
            contents are [fourteen, twelve, one, fourteen, twelve, two]

SELECT stringSet FROM ECEntity WHERE id LIKE ?1
getResultList returned a java.util.Vector
    elements are of type java.util.ImmutableCollections$SetN
            contents are [[fourteen, twelve, one], [fourteen, twelve, two]]

SELECT stringSetEC FROM ECEntity WHERE id=?1
getResultList returned a java.util.Vector
    elements are of type java.lang.String
            contents are [fourteen, twelve, one]

<<< END: testElementCollecti

If EclipseLink wants to reject this outright because the Jakarta Persistence specification does not require element collections to be selected by JPQL queries, that would be perfectly fine. But if EclipseLink doesn't reject it, it at least needs to get the behavior correct and return valid results.

[ajaypaul-ibm]

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[njr-11]

Approving. Looks like a very consistent copy of #30575 for JPA.

[ajaypaul-ibm]

#build (view Open Liberty Personal Build - ✅ completed successfully!)

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Code analysis and actions

DO NOT DELETE THIS COMMENT.

• 2 FAT files were changed, added, or removed.

• Check that the build did not break the affected FAT suite(s).

• Please describe in a separate comment how you tested your changes.

[ajaypaul-ibm]

@njr-11 I have incorporated the changes as per the review comments. Kindly take a look and approve at your convenience. Thank you!