[foreign-memaccess+abi] RFR: 8291639: Improve the ability to visualize a MemorySegment in human readable forms [v7]

[Per Minborg]

> This PR proposes to add a "Record Mapper" that allows `MemorySegment` instances to be projected onto `Record` types given `GroupLayout` instances.
> 
> Here is a simple example of how to use the mapper:
> 
> 
>     private static final GroupLayout POINT_LAYOUT = MemoryLayout.structLayout(
>             JAVA_INT.withName("x"),
>             JAVA_INT.withName("y"));
> 
>     MemorySegment segment =  MemorySegment.ofArray(new int[]{3, 4});
> 
>     Point point = POINT_LAYOUT.recordMapper(Point.class)
>           .apply(segment); // Point[x=3, y=4]
> 
> 
> I think the implementation can be improved later, for example by de-duplicating handling of arrays and maybe add recursive "un-pealing" of multidimensional arrays.

Per Minborg has updated the pull request incrementally with two additional commits since the last revision:

 - Break apart nested switch statements
 - Remove exactness variants

-------------

Changes:
  - all: https://git.openjdk.org/panama-foreign/pull/833/files
  - new: https://git.openjdk.org/panama-foreign/pull/833/files/94c781ef..f3377c8c

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=panama-foreign&pr=833&range=06
 - incr: https://webrevs.openjdk.org/?repo=panama-foreign&pr=833&range=05-06

  Stats: 442 lines in 2 files changed: 197 ins; 222 del; 23 mod
  Patch: https://git.openjdk.org/panama-foreign/pull/833.diff
  Fetch: git fetch https://git.openjdk.org/panama-foreign.git pull/833/head:pull/833

PR: https://git.openjdk.org/panama-foreign/pull/833