RFR: 8257184: Upstream 8252504: Add a method to MemoryLayout which returns a offset-computing method handle [v3]

[Jorn Vernee]

> This upstreams the patch from: https://github.com/openjdk/panama-foreign/pull/396
> 
> There were only some minor merge conflicts due to imports and some tests being replaced by java/foreign/TestNulls. All tests still pass, no other changes were needed.
> 
> CSR: https://bugs.openjdk.java.net/browse/JDK-8257187

Jorn Vernee has updated the pull request incrementally with one additional commit since the last revision:

  Update src/jdk.incubator.foreign/share/classes/jdk/incubator/foreign/MemoryLayout.java
  
  Co-authored-by: Maurizio Cimadamore <54672762+mcimadamore at users.noreply.github.com>

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/1468/files
  - new: https://git.openjdk.java.net/jdk/pull/1468/files/4b632628..c597f900

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=1468&range=02
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=1468&range=01-02

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/1468.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/1468/head:pull/1468

PR: https://git.openjdk.java.net/jdk/pull/1468