RFR: 8287244: Add bound check in indexed memory access var handle [v2]

[Maurizio Cimadamore]

> Constructing indexed var handles using the `MemoryLayout` API produces `VarHandle` which do not check the input indices for out-of-bounds conditions.
> While this can never result in a VM crash (after all the memory segment will protect against "true" OOB access), it is still possible for an access expression to refer to parts of a segment that are logically unrelated.
> 
> This patch adds a "logical" bound check to all indexed var handles generated using the layout API.
> Benchmarks are not affected by the check. Users are still able to create custom "unchecked" var handles, using the combinator API in `MethodHandles`.

Maurizio Cimadamore has updated the pull request incrementally with one additional commit since the last revision:

  Tweak javadoc for ValueLayout::arrayElementVarHandle

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/8868/files
  - new: https://git.openjdk.java.net/jdk/pull/8868/files/453392ae..a682cc03

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=8868&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=8868&range=00-01

  Stats: 17 lines in 1 file changed: 16 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8868.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8868/head:pull/8868

PR: https://git.openjdk.java.net/jdk/pull/8868