[foreign-memaccess+abi] RFR: 8291826: Rework MemoryLayout Sealed Hierarchy

[Per Minborg]

This PR is a significant refactor of the `MemoryLayout` sealed hierarchy and whose purpose is described more in detail in  https://bugs.openjdk.org/browse/JDK-8291826. In short, the main purpose is to allow pattern matching.

The objective of the PR is to fix the issues described above while retaining as much API compatibility as possible with the pre-PR API. No changes were needed in any of the existing tests for example.

The old sealed hierarchy prevented pattern matching with totality to be used and implied a number of other problems as illustrated in the picture below:

![graphviz (33)](https://user-images.githubusercontent.com/7457876/185412743-febeb3cf-aebc-4e2e-b78f-3b8ef87b0510.png)

Red nodes cannot be used in pattern matching. Light red nodes are implementations that are visible in the API. White nodes are interfaces.

After this PR has been integrated, an improved sealed hierarchy will exist as depicted here:

![graphviz (34)](https://user-images.githubusercontent.com/7457876/185413448-8435b23f-5ac4-4999-8b0a-0d6051a0d9be.png)

Gray "Impl" nodes are internal and not exported by the `java.base` module. White nodes are interfaces.

Below, the "Principal Totalities" for the new API are outlined:


var v0 = switch (memoryLayout) {
  case MemoryLayout ml -> 0;
};
var v1 = switch (memoryLayout) {
  case GroupLayout gl -> 0;
  case PaddingLayout pl -> 0; // leaf
  case SequenceLayout sl -> 0; // leaf
  case ValueLayout vl -> 0;
};
var v2 = switch (memoryLayout) {
  case PaddingLayout pl -> 0; // leaf
  case SequenceLayout sl -> 0; // leaf
  case ValueLayout vl -> 0;
  case StructLayout sl -> 0; // leaf
  case UnionLayout ul -> 0; // leaf
};
var v3 = switch (memoryLayout) {
  case PaddingLayout pl -> 0; // leaf
  case SequenceLayout sl -> 0; // leaf
  case StructLayout sl -> 0; // leaf
  case UnionLayout ul -> 0; // leaf
  case OfAddress oa -> 0; // leaf
  case OfBoolean ob -> 0; // leaf
  case OfByte ob -> 0; // leaf
  case OfChar oc -> 0; // leaf
  case OfDouble od -> 0; // leaf
  case OfFloat of -> 0; // leaf
  case OfInt oi -> 0; // leaf
  case OfLong ol -> 0; // leaf
  case OfShort os -> 0; // leaf
};
var v4 = switch (memoryLayout) {
  case GroupLayout gl -> 0;
  case PaddingLayout pl -> 0; // leaf
  case SequenceLayout sl -> 0; // leaf
  case OfAddress oa -> 0; // leaf
  case OfBoolean ob -> 0; // leaf
  case OfByte ob -> 0; // leaf
  case OfChar oc -> 0; // leaf
  case OfDouble od -> 0; // leaf
  case OfFloat of -> 0; // leaf
  case OfInt oi -> 0; // leaf
  case OfLong ol -> 0; // leaf
  case OfShort os -> 0; // leaf
};



 Additional improvements can be made later in a separate PR, including removing/improving some of the internal abstract classes.

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

Commit messages:
 - Add tests and update return types
 - Rework MemoryLayout Sealed Hierarchy

Changes: https://git.openjdk.org/panama-foreign/pull/710/files
 Webrev: https://webrevs.openjdk.org/?repo=panama-foreign&pr=710&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8291826
  Stats: 2702 lines in 21 files changed: 1793 ins; 732 del; 177 mod
  Patch: https://git.openjdk.org/panama-foreign/pull/710.diff
  Fetch: git fetch https://git.openjdk.org/panama-foreign pull/710/head:pull/710

PR: https://git.openjdk.org/panama-foreign/pull/710