8341243: Use ArraySupport.SOFT_MAX_ARRAY_LENGTH for max array size in java.base

[eirbjo]

Please review this cleanup PR which updates code and tests in java.base to consistently use jdk.internal.util.ArraySupport.SOFT_MAX_ARRAY_LENGTH when referring to the JVM's maximum array size implementation limit. Currently, instances of Integer.MAX_VALUE - 8 are found across the code base, with varying degrees of documentation. It would be good to consolidate on a single source of truth, with proper documentation.

This PR is a follow-up to #20905 where the same change was requested in java.util.zip.

My understanding is that javac will fold this constant value into the byte code of the compiled use sites, as such this change should not affect class loading or cause startup issues.

Instances selected for this PR were found searching for "Integer.MAX_VALUE - 8". The PR replaces these with ArraySupport.SOFT_MAX_ARRAY_LENGTH, while trimming or amending some code comments where appropriate. (SOFT_MAX_ARRAY_LENGTH already has a good explainer which does not need repetition at each use site).

I also searched for instances of Integer.MAX_VALUE - 1 and Integer.MAX_VALUE - 2, no convincing candidates were found.

Instances outside java.base were deliberately left out to limit the scope and review cost of this PR.

Tests updated to use SOFT_MAX_ARRAY_LENGTH are updated with the jtreg tag @modules java.base/jdk.internal.util.

Testing: No new tests are added in this PR, the noreg-cleanup label is added to the JBS. The five affected tests have been run manually. GHA tests run green.

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Issue

• JDK-8341243: Use ArraySupport.SOFT_MAX_ARRAY_LENGTH for max array size in java.base (Enhancement - P4)

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