RFR: 8139457: Array bases are aligned at HeapWord granularity [v24]

[Roman Kennke]

> See [JDK-8139457](https://bugs.openjdk.org/browse/JDK-8139457) for details.
> 
> Basically, when running with -XX:-UseCompressedClassPointers, arrays will have a gap between the length field and the first array element, because array elements will only start at word-aligned offsets. This is not necessary for smaller-than-word elements.
> 
> Also, while it is not very important now, it will become very important with Lilliput, which eliminates the Klass field and would always put the length field at offset 8, and leave a gap between offset 12 and 16.
> 
> Testing:
>  - [x] runtime/FieldLayout/ArrayBaseOffsets.java (x86_64, x86_32, aarch64, arm, riscv, s390)
>  - [x] bootcycle (x86_64, x86_32, aarch64, arm, riscv, s390)
>  - [x] tier1 (x86_64, x86_32, aarch64, riscv)
>  - [x] tier2 (x86_64, aarch64, riscv)
>  - [x] tier3 (x86_64, riscv)

Roman Kennke has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 40 commits:

 - Eliminate oopDesc::header_size()
 - Merge branch 'master' into JDK-8139457
 - Clarify comment on arrayOopDesc::max_array_length()
 - Remove debug output
 - Fix assert in collectedHeap
 - Add asserts in and around arrayOop::max_array_length()
 - Fix intendation in test
 - Remove stale method
 - Alexey's comments
 - Use uint64_t
 - ... and 30 more: https://git.openjdk.org/jdk/compare/622f5604...017a836b

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Changes: https://git.openjdk.org/jdk/pull/11044/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=11044&range=23
  Stats: 750 lines in 47 files changed: 505 ins; 146 del; 99 mod
  Patch: https://git.openjdk.org/jdk/pull/11044.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/11044/head:pull/11044

PR: https://git.openjdk.org/jdk/pull/11044